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THE  CHEMICAL  EXAMINATION 

OF  WATER,  FUEL, 
FLUE  GASES  AND  LUBRICANTS 


S.  W.  PARR 


".f  V 


THE  CHEMICAL  EXAMINATION  OF 

WATER,  FUEL,  FLUE  GASES 

AND  LUBRICANTS 


A  COURSE  FOR  ENGINEERING  STUDENTS 


CHEMISTRY  16 

As  given  in  the  Division  of  Applied  Chemistry  at  the 
UNIVERSITY  OF  ILLINOIS 


BY 

S.  W.  PARR 
Professor  of  Applied  Chemistry 


URBANA,  ILLINOIS 
1916 


COPYRIGHT  1911 
COPYRIGHT  1916 
BY  S.  W.  PARR 


CONTENTS 

PART  I:— LECTURES 

Chapter  I : — Boiler  Waters :  PAGE 

Source  and  character  of  mineral  content 5 

Effect  of  impurities 8 

Chemical   treatment 13 

Apparatus  for  applying  chemical  processes 18 

Rating  of  boiler  waters 23 

Type  waters  and  calculated  treatment 26 

Chapter "ll :— Fuels: 

Types,  relative  values 27 

Coal: 

Properties,    Classification 30 

Sampling  _ 32 

Moisture,    Calculations _ 43 

Unit  Coal,  Corrected  ash 46 

Calorimetric   measurements 49 

Table  of  average  values 60 

Coal  specifications  and  contracts 61 

Combustion,  Smoke 65 

Storage,  "Weathering 66 

Chapter  III : — Flue  Gases,  Significance  of  analytical  results „ 71 

Calculation  for  heat  losses 72 

Chapter  IV :: — Lubricants,  Types,  Properties 76 

PART  II :— LABORATORY  METHODS- 

Chapter  V : — Preliminary  experiments 79 

Standard  solutions 80 

Chapter  VI : — Boiler  water  analysis - 85 

Summary  and  calculations _ _ 92 

Chapter  VII : — Fuel  Analysis,  Proximate 94 

Heat  Values,  Peroxide  Calorimeter 97 

Sulphur  determination _ 103 

Heat  values,  oxygen  bomb 108 

Calculations 114 

Chapter  VIII : — Ultimate  analysis 115 

Total  carbon  by  volume 117 

Available  hydrogen 119 

Chapter  IX : — Flue  gas  analysis 120 

Chapter  X: — Oil  examination 122 

Index   .  .  128 


349279 


PRELIMINARY    STATEMENT 

This  work  is  intended  primarily  for  Juniors  in  Mechanical  and 
Railway  Mechanical  Engineering  at  the  University  of  Illinois.  From 
the  chemical  standpoint,  it  is  a  very  serious  problem  to  know  what  may 
profitably  be  attempted  in  the  way  of  analytical  methods  in  the  case 
of  students  whose  chemical  experience  is  meager.  But,  however  unsat- 
isfactory the  amount  of  preliminary  training,  it  is  obvious  that  the 
curriculum  in  Engineering  courses  is  already  overcrowded,  hence  the 
obtaining  of  a  better  prerequisite  in  chemistry  is  well  nigh  impossible. 
The  work  as  herein  outlined  is  the  result  of  ten  years  of  effort  to  make 
the  most  of  the  situation.  It  would  be  quite  too  much  to  claim  that  in 
the  evolution  of  the  work  a  satisfactory  status  has  been  attained.  It 
is  hoped,  however,  that  the  course  will  at  least  help  the  engineer  to  a 
better  understanding  of  the  literature  of  the  topics  considered  and  also 
to  an  appreciation  and,  consequently,  a  more  intelligent  use  of  data 
which  may  come  into  his  hands  from  the  chemist.  It  may  not  be  out  of 
place  to  state  further  that  the  course,  which,  at  the  first,  was  inaugu- 
rated with  no  little  misgiving,  has  more  than  justified  the  experiment. 
For  this  result  credit  is  due  the  students,  who,  from  year  to  year  have 
carried  the  work  through  with  a  responsiveness  which  has  been  the  main 
stimulus  in  developing  this  outline  into  its  present  form. 

Part  I  is  a  synopsis  only  of  the  lectures  given.  Part  II  consists 
essentially  of  laboratory  directions  for  the  analytical  methods  there 
undertaken.  The  time  allowance  for  lectures,  quizzes,  and  laboratory 
is  nine  hours  per  week  for  18  weeks.  The  amount  of  work  as  outlined 
is  such  that  the  average  student  covers  the  ground  in  the  time  prescribed. 

Special  acknowledgement  is  due  Dr.  H.  J.  Broderson  for  suggested 
improvements  in  the  present  edition  and  for  valued  assistance  in  the 
reading  of  proof. 


PART  I 

DESCRIPTIVE  OUTLINE 

CHAPTER  I 

BOILER  WATERS 

THEIR  EXAMINATION,  CHARACTER  AND  TREATMENT. 

Water  Analysis: — Waters  are  examined  for  two  very  different 
purposes.  First,  the  object  may  be  to  determine  the  potability  or 
sanitary  character  of  the  water;  and,  second,  it  may  be  desired  to 
learn  the  behavior  or  value  of  the  water  for  industrial  uses.  The  require- 
ments under  each  division  are  very  different.  In  order  to  be  sanitary, 
a  water  must  be  free  from  certain  forms  of  organic  matter  which  might 
indicate  possible  contamination  with  sewage  or  furnish  a  suitable  breed- 
ing medium  for  disease  germs.  Within  reasonable  limits,  the  amount  of 
mineral  constituent  is  of  little  importance.  On  the  contrary,  however, 
the  value  of  a  water  for  industrial  purposes  depends  very  largely  on 
the  kind  and  amount  of  the  dissolved  mineral  substance,  while,  as  a  rule, 
little  importance  is  attached  to  the  organic  material  present.  This  is 
especially  true  in  the  case  of  those  waters  which  are  to  be  used  for 
boiler  purposes,  and  it  is  this  phase  of  the  subject  which  is  of  immediate 
interest. 

Source  of  the  Mineral  Constituents: — Natural  waters  in  passing 
through  the  soil  come  in  contact  with  certain  products  of  decomposition 
and  decay.  Some  of  these  substances,  notably  carbon  dioxide,  humie 
acid,  etc.,  are  taken  up  by  the  waters,  in  which  condition  their  power 
to  dissolve  mineral  matter  is  greatly  increased.  In  this  way  the  decom- 
position of  feldspar,  limestone,  etc.,  is  constantly  going  on,  the  result 
to  the  percolated  water  being  that  there  is  taken  into  solution  varying- 
quantities  of  silica,  salts  of  iron,  aluminum,  magnesium,  sodium, 
potassium,  etc.  As  a  rule,  therefore,  the  less  contact  natural  waters 
have  had  with  the  soil,  or  the  more  insoluble  the  earthy  matter  with 
which  they  have  come  in  contact,  the  smaller  will  be  the  amount  of 
mineral  constituents  dissolved:  and,  conversely,  the  deeper  the  source 
of  supply,  the  greater  the  opportunity  for  dissolving  such  material, 
and  consequently  the  greater  will  be  the  amount  of  such  substances  in 

5 


6  THE.\CH£MICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

solution.  For  this  reason  it  has  been  sometimes  customary  to  divide 
waters  into  three  classes : — 

First;  Surface  water, 

Second;  Shallow  wells  and  spring  waters, 

Third;  Deep  wells  and  artesian  waters. 

Surface  waters  are  such  as  are  found  in  lakes,  streams,  and  artificial 
ponds,  and  with  these  might  also  be  considered  cistern  or  rain  waters; 
shallow  well  waters  may  be  considered  as  those  obtained  from  wells 
or  borings  which  extend  into  the  drift  not  to  exceed  30  or  40  feet; 
while  deep  well  waters  may  be  considered  those  that  are  obtained  from 
a  depth  of  over  100  feet.  These  divisions  are  not  sharply  drawn,  and, 
indeed,  the  classes  merge  into  each  other.  This  is  more  readily  seen 
from  the  fact  that  many  streams,  for  a  large  part  of  the  year  at  least, 
are  fed  by  waters  which  have  their  source  in  tile  drains  and  springs. 
The  system  of  underground  drainage  so  largely  carried  on  in  these 
days,  therefore,  gives  to  the  waters  of  smaller  streams  at  least  many 
of  the  characteristics  of  the  water  from  the  shallow  wells.  This  feature 
is  more  pronounced  during  the  dry  months  of  the  year,  as,  for  example, 
in  the  late  summer  and  fall.  The  amount  of  mineral  matter,  therefore, 
varies  inversely  as  the  volume  of  water  in  these  minor  streams.  On 
the  other  hand,  large  bodies  of  water  and  larger  streams,  especially 
those -in  districts  where  they  come  in  contact  with  the  more  insoluble 
formations,  are  remarkably  free  from  mineral  matter.  This  is  especially 
characteristic  in  the  waters  of  Lake  Superior,  and  in  many  of  the  rivers 
of  the  north-central  region  of  the  United  States.  In  certain  regions, 
also,  as  in  the  delta  of  the  Mississippi,  water-bearing  sands  are  some- 
times found  at  very  considerable  depths,  but  with  extremely  small 
amounts  of  mineral  matter  present. 

It  will  be  seen  from  the  above  discussion  that  any  classification 
based  merely  upon  the  source  of  a  water  will  have  little  practical  value. 
Before  attempting  any  classification,  however,  based  upon  the  character 
of  the  dissolved  mineral  constituents  it  will  be  necessary  to  review  the 
processes  by  which  these  substances  become  a  part  of  the  water,  and  to 
note  their  properties  and  behavior  under  the  conditions  of  actual  use 
in  steam  boilers. 

Chemical  Characteristics  of  the  Mineral  Constituents : — Calcium  car- 
bonate, CaC03,  and  magnesium  carbonate,  MgC03,  are  the  chief  consti- 
tuents of  lime  rock.  Finely  divided  particles  of  these  substances  exist 
throughout  all  the  clayey  deposits  of  the  drift  region.  The  percolating 
water  holding  carbon  dioxide,  C02,  in  solution  has  the  property  of  a 


SOLUTION  PROCESSES  7 

weak  acid,  H20  +  CO2  =  H2C03,  and  in  this  form  is  a  solvent  for  the 
above  substances,  forming  bicarbonates,  thus: 

CaC03  +  H2C03  =  CaH,(C03).> 
MgC03  +  H2C03  =  MgH2(C03)2 

These  dissolved  bicarbonates  are  readily  broken  down  by  heat, 
thus : 

CaH2(CO3),  =  CaC03  +  H20  +  C02 

The  water  alone  with  the  carbon  dioxide   gas  driven   out  of  it  is  not 
a  solvent  for  calcium  carbonate,  and  the  latter  is  precipitated. 

Feldspars  of  various  sorts  are  usually  distributed  throughout  the 
drift  deposits.  These  also  are  slowly  decomposed  by  carbonated  waters 
thereby  adding  to  the  water  compounds  of  sodium,  potassium,  iron  and 
aluminum,  as  well  as  hydra  ted  silica,  which  is  also  soluble.  The  general 
type  of  this  reaction  may  be  shown,  thus : 
Al203.K20.6Si02  +  2H2C03  ==  Al,O3.2Si02.2H20  +  K2C03  +  4  Si02 

FELDSPAR  KAOLIN 

In  this  way  complex  or  impure  rocks  may,  upon  their  decompo- 
sition, yield  small  quantities  not  only  of  lime  and  magnesium  in  solution 
as  bicarbonates,  but  also  iron  in  a  bicarbonate  form,  as  well  as  salts  of 
sodium,  potassium,  and  silicic  acid.  This  result  would  be  more  readily 
understood  if  we  were  to  enter  into  a  study  of  the  composition  of  the 
drift,  especially  of  a  region  like  this  where  the  glacial  clay  has  a  very 
considerable  admixture  of  ground  rock  such  as  feldspar,  hornblend, 
mica,  dolomite,  etc.  Moreover,  since  all  drift  formation  has  been  depos- 
ited in  contact  with  or  by  means  of  sea  water,  we  expect  a  greater  or 
less  amount  of  mineral  substances  to  be  present  due  to  such  water; 
namely,  sodium  chloride,  calcium  sulphate,  etc. 

Solubility  of  Gypsum: — We  are  familiar  with  the  solubility  of 
sodium  chloride,  but  calcium  sulphate  or  gypsum  is  also  soluble, 
although  to  a  less  degree,  and  this  without  the  aid  of  carbon  dioxide. 
Its  solubility,  for  example,  may  be  illustrated  by  the  following  table : 

TABLE  I 

SOLUBILITY  OF  GYPSUM 
(CaS04+2H20). 

1  part  dissolves  in  about    500  parts  of  water  at  ordinary  temperature 
1  part  dissolves  in  about  1200  parts  of  water  at  250  Degrees  F. 
1  part  dissolves  in  about  1800  parts  of  water  at  300  Degrees  J1. 
1  part  dissolves  in  about  3800  parts  of  water  at  325  Degrees  F. 


8  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

From  the  above  facts  it  may  be  readily  understood  how  the  mineral 
constituents  come  to  be  dissolved  in  all  underground  waters.  The  kind, 
amount,  and  properties  of  these  substances  indicate  directly  the  behavior 
of  a  water  when  used  for  boiler  purposes.  Almost  without  exception 
their  presence  is  objectionable  for  reasons  which  will  be  evident  from 
the  following  discussion. 

Effects  of  Impurities: — The  difficulties  which  attend  the  use  of 
water  in  the  generation  of  steam  are  three  in  number : 

First,  mineral  scale  is  formed  upon  the  shell,  flues,  and  sheets; 
second,  foaming  or  priming  may  occur;  and,  third,  the  water  may  have 
corrosive  action  and  weaken  the  metal  of  which  the  boiler  is  composed. 

The  constituents  of  a  water,  therefore,  naturally  group  themselves 
under  these  three  heads : 

1.  Scaling  Ingredients. 

2.  Foaming  Ingredients. 

3.  Corrosive  Ingredients. 

Scaling  Ingredients:  Scaling  ingredients  are  always  considered  as 
including  silica  and  any  combination  of  iron,  aluminum,  calcium,  and 
magnesium.  Since  the  formation  of  scale  is  the  most  common  and 
perhaps  the  most  evident  difficulty  which  accompanies  the  use  of  a 
boiler,  it  has  sometimes  been  made  the  basis  of  a  classification  for 
waters.  At  a  meeting  of  the  American  Association  of  Railway  Chem- 
ists at  Buffalo,  New  York,  May  24,  1887,  the  following  schedule  of 
classification  was  adopted.  Waters  containing  varying  quantities  of 
scaling  material  per  United  States  gallon  were  graded  as  in  the  table 
below : 

TABLE  II 

CLASSIFICATION  OF  WATERS  BY  THE 
ASSOCIATION  OF  RAILWAY  CHEMISTS 

Below  8  grains very  good 

8  to  15  grains - good 

15  to  20  grains fair 

20  to  30  grains poor 

30  to  40  grains bad 

over  40  grains very  bad 

In  tfci$  table  the  first  line  was  added  by  the  C.  B.  &  Q.  By.  to  fit 
the  case  of  Lake  Michigan  water,  which  has  approximately  8  grains  or 
less  per  gallon. 


EFFECT  OF  SCALE  9 

This  classification  is  relative  only,  since  a  wider  study  of  the 
subject  has  indicated  the  necessity  of  taking  into  the  account  the  kind 
of  scale  which  would  form  and  the  other  ingredients  in  addition  to 
those  which  produce  scale.  The  scale  when  formed,  may  be  dense  and 
flint-like  or  open  and  porous.  These  characteristics  result  from  the 
various  types  of  mineral  content  involved.  In  general,  a  hard,  flinty 
scale  is  due  to  the  presence  of  calcium  or  magnesium  sulphates;  while, 
in  waters  in  which  only  the  carbonates  of  these  substances  are  present, 
the  scale  will  be  more  open  and  friable.  Indeed,  a  very  large  number 
of  waters  are  met  with  where  only  carbonate  hardness  is  present.  In 
these  cases  the  major  part  of  the  incrusting  solids  appears  as  mud  or 
sludge.  For  these  and  other  reasons  the  above  classification  has  not  met 
the  needs  of  the  case  and  has,  indeed,  not  been  adopted  to  any  con- 
siderable extent.  A  much  more  practical  classification  would  take 
account  of  all  of  the  various  constituents  and  the  characteristics  for 
which  they  are  responsible.  The  method  of  classification  devised  by  the 
Chicago,  Burlington  &  Quincy  Railroad  is  based  on  the  amount  of 
these  various  constituents.  Since  the  full  meaning  of  the  same  can  be 
better  understood  later,  it  is  reproduced  at  the  end  of  this  chapter. 

Effect  of  Scale : — Boiler  scale  is  a  disadvantage  for  the  reason  that : 
First,  it  retards  the  transmission  of  heat ;  second,  it  promotes  the  forma- 
tion of  a  high  temperature  in  the  plates,  with  a  possibility  of  softening 
the  same ;  third,  the  sudden  rupture  or  opening  up  of  the  scale  may 
admit  water  to  the  highly  heated  metal,  forming  hydrogen  and  oxygen ; 
fourth,  the  higher  temperature  of  the  steel  thus  maintained,  even  though 
not  reaching  the  danger  point,  promotes  the  absorption  of  sulphur  and 
oxygen  and  thus  causes  a  deterioration  of  the  metal.  Doubtless  the 
chief  item  in  this  list,  by  reason  of  its  continuous  and  total  aggregate 
effect,  is  the  decrease  of  heat  conductivity,  requiring  a  larger  amount 
of  fuel.  Authorities  differ  as  to  the  extent  of  loss.  A  conservative 
estimate  would  place  the  loss  of  fuel  at  10%  for  each  1/16  of  an  inch 
in  thickness  of  the  scale.  The  difficulties  attending  the  estimation  of 
the  fuel  loss  are  great,  and  it  is  to  be  expected  that  a  rather  wide 
range  of  results  is  found  in  the  published  data.* 

A  test  of  the  steaming  efficiency,  made  upon  an  Illinois  Central 

locomotive  by  the  University  of  Illinois  in  1898  and  described  in  the 

Railway  Gazette  for  the  following  year,  indicated  a  loss  of  heat,  with  a 

*The  effect  of  scale  on  the  Evaporation  of  a  Locomotive  Boiler.     By  L.   P. 

Breckenridge.    R.  R.  Gazette,  Vol.  31,  new  series,  p.  60,  1899. 

Am.  Ry.  Eng.  Asscn.,  1914  p.  692 :  " it  is  concluded  that  the  saving 

of  $977-  per  locomotive  represents  7  cents  per  pound  of  excess  scaling  matter  enter- 
ing the  boiler  ". 

Bulletin  No.  11,  Eng.  Exp.  Sta.,  U.  of  I. 

Am.  Ry.  Eng.  &  Maint.  of  Way  Assn.,  Jan.,  1907,  p.  41,  etc. 


io  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

scale  averaging  3/64"  in  thickness,  amounting  to  9.6  per  cent.  The 
same  engine  was  tested  before  overhauling  at  the  shops  and  was  re- 
turned after  cleaning  for  the  comparative  test.  An  interesting  compu- 
tation was  made  on  the  same  road  at  a  much  earlier  date,  in  which 
the  performance  sheets  for  120  locomotives  were  taken  with  reference 
to  the  comsumption  of  coal  before  overhauling,  and  these  results  were 
compared  with  the  coal  consumed  for  the  three  months  immediately 
following  such  a  cleaning,  with  an  average  for  the  120  engines  of  almost 
exactly  10  per  cent  in  favor  of  the  scale-free  condition.  Many  other 
tests  have  subsequently  been  made  more  or  less  confirmatory  of  these 
results. 

Foaming  Ingredients: — The  non-scaling  or  foaming  ingredients 
are  considered  to  be  the  salts  of  the  alkalies,  such  as  sodium  chloride, 
sodium  sulphate,  sodium  carbonate,  potassium  chloride,  potassium  sul- 
phate, potassium  carbonate,  etc.  Other  conditions  contribute  to  the 
tendency  of  water  to  foam,  such  as  the  presence  of  organic  matter, 
especially  such  substances  as  may  form  soap.  The  presence  of  finely 
divided  solids  in  suspension  is  also  a  contributing  cause. 

The  objections  against  foaming  may  be  states  as  follows:  First, 
the  rising  of  the  water  in  the  gauge  glass  or  blow  off  cocks  makes  it 
difficult,  if  not  impossible,  to  know  the  height  of  the  water  in  the  boiler ; 
second,  the  discharge  of  wet  steam  or  of  steam  carrying  a  considerable 
Quantity  of  water  is  exceedingly  wasteful  of  heat  and  makes  it  difficult 
to  keep  up  the  steam  pressure;  third,  there  is  danger  of  large  quanti- 
ties of  water  getting  into  the  cylinders  where,  by  reason  of  its  incom- 
pressibility  and  inability  to  pass  quickly  out  of  the  ports,  a  cylinder 
head  may  thereby  be  blown  off;  and,  fourth,  the  grit  carried  along  with 
the  water  promotes  the  cutting  of  the  walls  of  the  cylinders  and  valve 
seats,  thus  making  a  re-boring  of  the  cylinders  necessary. 

Concerning  the  causes  which  promote  foaming,  they  are  not  so 
easy  to  define  or  classify  as  in  the  case  of  scaling,  and  they  do  not  always 
relate  directly  to  the  character  of  the  dissolved  mineral  substance.  The 
tendency  to  foam  varies  greatly,  for  example,  with  the  two  general  types 
of  boilers  employed,  those  used  for  stationary  purposes,  and  the  loco- 
motive type.  It  might  be  said,  indeed,  that  to  the  above  mentioned 
conditions  of  the  water  might  be  added  the  nature  of  the  spaces  in 
which  the  generation  of  steam  takes  place.  A  net- work  of  stay-bolts 
and  braces  in  a  steaming  space  of  small  volume  at  best  will  be  more 
conducive  to  foaming  than  the  opposite  conditions.  The  structure  and 
steaming  capacity  of  the  locomotive,  therefore,  greatly  increase  the  ten- 
dency of  this  type  of  boiler  to  foam.  Tests  on  numerous  railroads  pretty 
generally  agree  upon  the  following  facts  concerning  the  foaming  in  loco- 


CORROSIVE  INGREDIENTS  11 

motives.  When  a  density  of  the  water  due  to  the  presence  of  alkali 
sulphate  or  chloride  reaches  approximately  100  grains  to  the  gallon, 
foaming  is  apt  to  occur,  especially  when  the  engine  is  put  under 
heavy  work.  This  means  that  in  the  raw  water,  before  condensation 
has  been  carried  on,  a  content  of  25  grain  per  gallon  would  reach  the 
foaming  stage  when  3  or  4  tankfuls  had  been  taken  into  the  boiler. 
However,  a  wide  variation  is  due  to  the  type  of  foaming  ingredients, 
since  a  less  amount  of  alkali  salt  will  cause  foaming  where  part 
of  the  substance  is  alkali  carbonate,  Na2C03,  or  soda  ash.  Where 
much  organic  matter  also  is  present,  a  still  less  amount  of  free  alkali 
will  cause  foaming.  Indeed,  cases  have  been  met  with  where  15  to  25 
grains  per  gallon  of  alkali  salts  have  produced  foaming,  when  one-half, 
for  example,  of  such  salts  were  in  the  form  of  alkali  carbonates,  ac- 
companied by  a  very  considerable  amount  of  organic  matter.  Foaming 
in  stationary  boilers  would  scarcely  be  caused  by  double  the  amount 
mentioned  above. 

Corrosive  Ingredients: — Much  disagreement  exists  regarding  the 
causes  of  corrosion.  Certain  conditions  will  produce  galvanic  action 
between  different  metals  used  in  construction,  or  even  between  different 
parts  though  made  of  the  same  metal,  and  this  action  eats  away  the 
metallic  surfaces.  Flawrs,  cinder  scales,  oxide  nodules,  etc.,  will,  prob- 
ably for  a  similar  reason,  produce  pitting.  Along  sharp  angles  of  con- 
struction, wrhere  the  metal  has  been  put  under  strain,  corrosion  will 
frequently  occur.  Carbonic  acid  gas  or  oxygen,  when  dissolved  in  water, 
are  solvents  for  iron.  Of  course,  the  heat  soon  drives  these  gases  out  of 
the  water,  but  corrosion  in  the  vicinity  of  the  feed  inlet  may  be  due 
to  this  cause.  Some  waters  percolate  through  culm  heaps  or  coalmine 
refuse  or  drainage  and  have  produced  in  them  free  sulphuric  acid 
from  the  oxidation  of  iron  pyrites,  or  they  may  take  up  sulphate  of  iron 
or  aluminium,  all  of  which  chemicals  render  a  water  positively  and 
vigorously  corroding. 

Nitrates  are  seldom  encountered,  but,  when  present  in  any  consider- 
able amount,  are  strongly  corroding.  Calcium  and  magnesium  chlorides 
are  also  strongly  corroding.  But,  after  all,  it  may  be  noted  that  many 
conditions  can  exist  to  neutralize  the  corrosiveness  of  a  water.  For 
instance,  there  may  be  formed  a  hard,  dense  scale  which  will  effectually 
protect  the  iron.  In  this  case,  however,  we  would  expect  to  see  some 
tendency  toward  corrosion  and  pitting  under  the  scale. 

If,  now,  we  attempt  to  classify  waters  according  to  the  mineral 
constituents  above  outlined,  we  would  have : 

Class  I. — This  class  includes  such  waters  as  have  present  free  sodium 
carbonate  or  more  than  enough  sodium  to  unite  with  the  sulphate, 


12  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

chloride,  and  nitrate  radicals  or  ions.  There  would  be  left,  therefore, 
only  carbon  dioxide,  C02,  to  unite  with  the  remaining  sodium  and  also 
the  calcium,  magnesium,  and  iron.  Such  waters  have  only  temporary 
hardness,  there  being  no  sulphates  of  calcium  or  magnesium.  Upon 
boiling  or  using  in  the  steam  boiler,  only  a  sludge  forms  instead  of 
scale.  The  carbonates  are  all  in  the  bicarbonate  form  and,  hence,  are 
stable  in  the  cold,  but  decompose  upon  heating.  Waters  of  this  class  are 
very  widely  distributed  throughout  the  drift  region,  and  the  source  is 
usually  from  deep  wells. 

Class  II. — The  waters  of  this  class  contain  calcium  or  magnesium 
sulphate  as  well  as  bicarbonates,  but  not  the  chlorides  of  these  elements. 
They  have,  therefore,  permanent  hardness  and  form  a  hard,  flinty 
scale.  Such  waters  are  usual  in  surface  supplies  and  in  most  shallow 
wells. 

Class  III. — This  includes  such  waters  as  contain  corroding  salts 
or  free  acid  in  solution,  such  as  the  chlorides  or  nitrates  of  magnesium 
or  calcium,  the  sulphate  of  iron  or  free  sulphuric  acid.  Such  waters 
are  infrequent  but,  because  of  their  corroding  character,  should  be 
recognized  when  met  with.  •.  ' 

The  Chemical  Treatment  of  Boiler  Waters: — From  what  has  pre- 
ceded it  will  be  readily  understood  that  the  treatment  of  boiler  waters 
must  follow  closely  along  the  line  of  the  chemical  character  of  dissolved 
ingredients,  with  a  view  also  to  the  properties  which  various  ingredients 
impart  to  the  water.  In  the  first  instance,  it  must  be  remembered  that 
all  natural  water  is  strongly  impregnated  with  carbon  dioxide.  We 
should  recall  again  the  fact  that  the  presence  of  this  gas  in  the  water 
has  furnished  a  solvent  condition  which  has  resulted  in  the  formation  of 
bicarbonates,  especially  of  lime,  magnesium,  and  iron. 

But  other  soluble  substances,  we  have  already  seen,  also  enter  into 
the  water,  notably  the  sulphates  of  lime,  magnesium,  sodium,  etc.  Now, 
because  of  the  fact  that  the  compounds  of  the  first  group  of  substances 
are  easily  decomposed  by  heat  and  thus  discharged  from  solution,  we 
have  a  sub-division  of  scaling  ingredients  into 

(A)  Those  which  are  designated  as  constituting  temporary  hard- 
ness and  (B)  Those  which  constitute  permanent  hardness  of  water.  The 
first  division  is  present  in  all  waters  and  includes  the  larger  part  of  the 
scaling  matter;  the  latter  is  variable  in  amount  and  frequently  absent, 
so  far  as  the  scaling  constituents  are  concerned.  These  two  general 
divisions  or  types  of  scaling  material  must  be  borne  in  mind,  because 
they  form  the  basis  of  all  practical  methods  for  water  treatment,  indeed, 
each  division  represents  a  process  or  a  method  which  must  be  followed 


SCALING  MATERIAL  AND  ITS  REMOVAL 


for  the  removal  of  these  substances, 
trated  by  the  following  outline: 


This  may  be  more  clearly  illus- 


TABLE  III 
SCALING  MATTER  AND  TREATMENT 


'Div.  I. 

-LJ.A.UCQO         V^V 

Bicarbon-* 

CaH,(C03)2 

Scaling 

ates  as  :  — 

Mg 

matter 

"R^o              *  ' 

is  prin-  ^ 

cipally 

com- 
posed  of 

Div.  II. 

Sulphates, 

MgSo, 

Ca    " 

as: 

Fe 

For  this 
Div.  use 


The 
results  are 


CaC03+2H20 

CaC03+CaC03-f2H00 

MgC03+CaCOa+2H00 

^FeC03*+CaC03+2H20 


MgC03+Na4SO 
CaC03+Na2S04 

FeCO*3+Na2S04 


For  this 
Div.  use 
NaoC03. 

fThe 
results 
are 

*This  substance  quickly  breaks  down  into  Fe(OH)8  thus: 
2FeCOa  +  3H20  +  O  =  2Fe(OH)8  +  2CO2 

It  will  be  readily  seen  from  this  outline  that  the  first  division,  carry- 
ing the  bicarbonates,  may  be  removed  from  the  water  either  by  heat  or  by 
the  addition  of  some  chemical  which  will  absorb  the  '  *  excess ' '  and  ' '  bicar- 
bonate" carbon  dioxide.  If  we  were  to  depend  upon  heat  for  this  work,  it 
would  be  a  long  process  for  the  reason  that  ordinarily  these  bicarbonates 
are  not  completely  broken  down  except  upon  rather  prolonged  boiling, 
say  for  15  or  20  minutes  or  even  %  hour,  and  this  again  would  indicate 
the  impracticability  of  such  a  method,  because  of  the  expense  involved. 

Treatment  with  Lime,  Ca(OH)^: — Since  hydrated  lime  reacts  at 
ordinary  temperatures  and,  moreover,  is  the  least  expensive  of  the 
possible  reagents,  it  is  made  use  of  to  react  with  the  C02  of  Div.  I  of 
Table  III. 

In  measuring  the  amount  of  Ca(OH)2  needed  for  treating  a  water, 
it  must  be  borne  in  mind  that  the  C02  dissolved  as  H,C03  will  react 
with  the  Ca(OH)2  the  same  as  the  bicarbonates.  Hence  we  have  a  series 
of  reaction  thus: 


a       H2C03 

fCaH,(C03)2 

b    ^MgH2(C03)2 

lFeH2(C03)2 


CaC03  +  2H,0 

CaCO3  +  CaC03 
MgC03  +  CaCOo 
FeC03  +  CaC03 


14  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL;  ETC. 

The  total  C02  to  be  thus  taken  care  of  is  designated  as  (a)  "excess'* 
or  "free"  carbon  dioxide,  and  (&)  "half  bound"  or  "bicarbonate" 
carbon  dioxide.  It  is  necessary  to  measure  the  amount  of  free  carbon 
dioxide  by  titrating,  say  200  c.c.  of  the  water  with  N/50  Na2C03,  using 
phenolphthalein  as  indicator.  Each  c.c.  of  this  reagent,  therefore, 
represents  an  equivalent  of  0.001  gram  in  terms  of  CaC03.* 

Therefore,  5  times  the  number  required  for  200  c.c.  of  water  would 
represent  the  equivalent  in  1000  c.c.  or  1  liter  of  water.  This  would 
represent  milligrams  per  liter  which  is  the  same  as  parts  per  million. 
Parts  per  million  multiplied  by  0.0583  =  grains  per  gallon.** 

The  "bicarbonate"  carbon  dioxide  is  determined  by  titrating  a 
measured  volume  of  the  water  with  N/10  sulphuric  acid,  using  methyl 
orange  as  indicator.  (See  p.  86,  Part  II.)  Each  cubic  centimeter  of 
N/10  sulphuric  acid  is  equivalent  to  0.005  gram  CaC03.  Therefore,  if 
200  c.c.  of  water  be  titrated,  each  c.c.  of  acid  used  corresponds  to  0.025 
grams,  that  is  25  milligrams  per  liter  or  25  parts  per  million  bicar- 
bonate carbon  dioxide,  measured  in  terms  of  CaC03. 

The  above  estimation  of  the  "free"  and  "half  bound"  carbon 
dioxide  would  represent  all  of  the  conditions  to  be  taken  into  consid- 
eration in  connection  with  the  lime  treatment  except  for  the  slight 
irregularity  in  the  behavior  of  one  element.  The  magnesium  carbonate, 
especially  in  the  presence  of  other  salts,  is  soluble  to  an  extent  which 
makes  it  advisable  to  carry  the  reaction  one  step  further  and  provide 
for  the  formation  of  magnesium  hydroxide  which  compares  favorably  as 
to  insolubility  with  the  calcium  carbonate.  This  is  effected  by  adding 
enough  extra  Ca(OH)2  to  correspond  to  the  magnesium  present.  By 
direct  determination,  therefore,  of  the  magnesium  and  the  calculation 
of  the  same  to  the  calcium  carbonate  equivalent,  we  have  the  necessary 
correction  indicated  for  this  element.  By  adding  the  calcium  carbonate 
equivalent  thus  found  to  the  factor  as  derived  above  by  titration  with 
N/V0  sulphuric  acid,  we  have  a  corrected  calcium  carbonate  equivalent 
for  the  bicarbonate  carbon  dioxide  plus  the  magnesium  present. 

Having  thus  determined  the  amount  of  ' '  excess ' '  and  ' '  half  bound ' ' 
carbon  dioxide  plus  the  magnesium,  in  terms  of  CaCO3,  the  amount 
of  reagent  as  CaO  for  the  total  CaC03  equivalent  would  be  in  the  ratio 
of  56  :  100.  To  transfer  to  a  unit  of  1000  gallons,  multiply  values  for 
1  gallon  by  1000;  and  to  transfer  grains  to  pounds  avoirdupois,  divide 

*The  molecular  weight  of  CaCO5  is  100.  This  is  a  bivalent  molecule,  hence  the 
univalent  or  hyrdogen  equivalent  would  be  50.  and  the  N/5o  value  would  be  I.  gram 
per  looo.  c.c.  Hence  I  c.c.  would  have  a  CaCOs  equivalent  of  o.ooi  gram. 

**One  gallon  weighs  58330  grains  hence  1/1,000,000  of  a  gallon  or  i  part  per 
million  weighs  .0583  grains. 


USE  OF  LIME  AND  SODA  ASH  15 

by  7000.  Hence,  '1/7  of  56/ioo  or  -08  times  the  grains  per  gallon  of  total 
calcium  carbonate  equivalent  represents  the  pounds  of  CaO  reagent 
needed  for  each  1000  gallons  of  water  in  removing  or  correcting  for 
these  ingredients. 

In  the  case  of  common  or  commercial  reagents  used  in  water  treat- 
ment, the  impurities,  of  course,  must  be  allowed  for. 

Where  the  lime  is  added  in  the  form  of  a  clear  solution  of  Ca(OH)2, 
the  latter  is  dissolved  to  the  point  of  saturation  and  this  concentrated 
solution  becomes  the  reagent. 

The  solubility  of  CaO  is  about  78  grains  per  gallon  cold,  (60°F). 

7000 
Hence  l/78th  gallon  of  lime  water  contains  1  grain  of  CaO,  and     no 

/o 

would  represent  the  number  of  gallons  necessary  to  hold  1  pound  of 
CaO  in  solution.  Therefore, 

Xo.  gals,  of  sat.  lime 
water  required  to  remove 


or  7-17+  =  the  total  calcium  carbon- 

of  CaCOa  ate  equivalent  in  I000 

equivalent  gallons  of 


The  solubility  of  CaO  decreases  as  the  temperature  of  the  water 
increases.  It  should  be  remembered,  also,  that  CaO  slakes  to  Ca(OH)2 
and  it  is  really  the  solubility  of  the  latter  compound  which  is  involved. 
Usually,  however,  the  reference  is  made  to  the  solubility  of  CaO  as  the 
basis.  Thus,  by  calculating  from  Lamy's  tables  (C.  E.  Vol.  86,  p.  333), 

78  grains  CaO  will  saturate  one  U.  S.  gallon  at     60°  F. 

70  grains  CaO  will  saturate  one  U.  S.  gallon  at     86°  F. 

58  grains  CaO  will  saturate  one  U.  S.  gallon  at  112°  F. 

51  grains  CaO  will  saturate  one  U.  S.  gallon  at  140°  F. 

33  grains  CaO  will  saturate  one  U.  S.  gallon  at  212°  F. 

Recently  the  market  has  come  to  be  supplied  with  pulverized  dry 
lime  in  the  hydrated  form.  To  find  the  solubility  by  weight  of  this 
material,  calculate  the  above  amounts  to  the  equivalent  of  Ca(OH)2. 
Thus, 

56      :  74       ::         78       :       x 

CaO       Ca(OH)2      gr.CaO      gr.Ca(OH), 

Whence,  78  grains  CaO  =  103  grains  Ca(OH)2,  which  would  rep- 
resent the  solubility  per  gallon  at  60°  F.  of  pure  material. 

Treatment  with  Soda  Ash,  Na2COz.  —  Of  the  substances  sufficiently 
cheap  to  be  available,  sodium  carbonate  or  ''soda  ash"  is  by  far  the 


16  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

best  adapted  for  division  II  of  Table  III,  or  those  ingredients  causing 
the  permanent  hardness  of  the  water.  No  reaction  or  change  in  solubil- 
ity by  heating  can  be  effective,  though  many  attempts  to  remove  the 
sulphate  by  reason  of  the  less  solubility  of  calcium  sulphate  in  hot  water, 
(as  indicated  in  Table  No.  I),  have  been  attempted.  With  this  class 
of  substances,  it  is  more  effective  to  remove  them  as  carbonates,  but 
this  must  be  brought  about  by  the  addition  of  a  soluble  carbonate  salt, 
the  cheapest  of  which  is  sodium  carbonate  or  "soda  ash",  Na2C03,  as 
above  indicated. 

To  measure  the  amount  of  "soda  ash",  Na2C03,  necessary  for  the 
precipitation  of  the  sulphates  of  magnesium,  calcium,  and  iron  or  per- 
manent hardness,  read  carefully  paragraph  IV  on  page  87  of  Part  II. 

The  reactions  involved  may  be  represented  as  follows: 

CaS04  +  Na,C03  —  CaC03  +  Na2S04 
MgS04  +  Na2"COs  =  MgC03  +  Na2S04 

The  amount  of  "soda  ash"  used  up  in  this  reaction  is  directly  the 
measure  of  this  substance  to  be  used  in  treating  the  water.  Thus : — If 
200  c.c.  of  water  were  taken,  then  5  times  the  number  of  c.c.  of  N/10 
Na2C03  X  0.0053  would  represent  the  weight  in  grams  per  liter  of 
Na2C03  required.  This  multiplied  by  1000  =  milligrams  per  liter  and 
this  multiplied  by  0.0583  would  give  the  grains  per  gallon  required 
directly  in  terms  of  "soda  ash".  Multiplying  this  by  1/7  would  give  the 
number  of  pounds  needed  per  thousand  gallons.  Where  magnesium 
salts  are  present  as  part  of  the  permanent  hardness,  the  MgC03  formed 
as  indicated  above  is  to  be  precipitated  as  Mg(OH)2,  the  same  as  under 
temporary  hardness.  Hence,  all  magnesium  compounds  call  for  an 
equivalent  of  Ca(OH)2  in  addition  to  the  primary  reagent  needed.  This, 
however,  is  provided  for  in  the  method  of  analysis  which  determines 
all  of  the  magnesium,  whatever  the  form  in  which  it  is  present;  and 
the  secondary  reagent,  Ca(OH)2,  for  its  removal  has  been  considered 
under  the  preceding  topic;  viz.,  "Treatment  with  Lime".  A  double 
reaction  is  thus  provided  for  magnesium,  whether,  the  combination  be 
that  of  a  bicarbonate,  a  sulphate,  or  a  chloride. 

Industrial  Methods: — While  in  this  discussion  the  reactions  involved 
in  the  purification  of  water  have  been  considered  separately  and  as 
two  distinct  processes,  in  practice  they  are  combined  into  one  opera- 
tion; that  is,  the  calculated  amount  of  lime  for  treating,  say,  1000 
gallons  of  raw  water  has  incorporated  with  it  the  amount  of  soda  ash 
as  indicated  by  the  sulphate  or  permanent  hardness  per  1000  gallons, 
and  the  two  reagents  thus  combined  are  added  directly  to  the  water. 

Very  many  mechanical  devices  for  automatically  measuring  the 
correct  amount  of  each  reagent  are  in  use,  depending  in  the  main  upon 


INDUSTRIAL  METHODS  OF  PURIFICATION  17 

the  principle  that  a  given  weight  or  volume  of  the  incoming  raw  water 
shall  operate  certain  mechanical  arrangements,  whereby  the  proper 
amount  of  chemical  is  discharged  into  the  water.  The  devices  are  of 
two  general  types: — the  continuous  and  the  intermittent.  In  the  con- 
tinuous type  the  raw  water  flows  into  the  apparatus  and  is  discharged 
in  the  purified  form  ready  for  use.  In  the  intermittent  type  the  raw 
water  is  made  to  flow  through  a  mechanical  measuring  arrangement, 
whereby  the  chemicals  in  the  proper  proportion  are  added,  after  which 
the  water  is  brought  into  a  large  settling  tank  for  the  time  element  to 
enter  in  for  the  accomplishing  of  the  reaction  involved  and  also  the 
settling  out  of  the  precipitates.  Both  types  are  effective,  the  essential 
point  in  any  case  being  that  the  automatic  devices  for  measuring  the 
reagents  be  exact  and  unfailing  in  their  operation.  Illustrations  are 
given  below  of  representative  devices  for  each  type.  They  have  been 
selected  primarily  with  reference  to  their  adaptability  in  the  matter  of 
illustrating  the  principles  of  water  treatment  as  outlined  in  the  text. 

Arguments  are  plentiful  for  the  adoption  of  some  form  of  water 
purification  for  practically  every  sort  of  industrial  use.  For  domestic 
and  laundry  purposes  the  softening  of  the  water  supply  by  means  of 
the  soap  employed  is,  theoretically  at  least,  far  more  expensive  than 
doing  the  same  work  with  soda-ash  and  lime.  The  various  railway  sys- 
tems for  the  most  part  make  use  of  purification  plants  for  their  service 
waters.  One  company  with  34  treating  plants  on  its  various  lines  shows 
a  summary  for  1915  as  follows  :* 

Total  consumption  treated  water _ 604,468,087  gallons 

Total  scaling  material  removed  by  treatment...     1,816,837  pounds 

Saving  in  fuel,  repairs,  etc.,  estimated  at  7c 

per  pound  of  incrustants  removed $127,171.00 

Cost  of  treatment,  Labor,  Chemicals,  Mainte- 
nance, plus  10%  on  investment 26,017.00 


Total  net  saving $100,454.00 

Cost  of  34  treating  plans 70,450.00 


'Communicated  by  R.  C.  Bardwell,  Chief  Chemist,  Union  Pacific  Ry.,  K.  C. 


iS 


THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


FIG.   i     EUREKA   WATER   SOFTENER,    CONTINUOUS    SYSTEM,   AS    SUPPLIED   BY   DODGE 

MANUFACTURING  Co.,  MISHAWAKA,   IND. 

The  description  of  the  parts  can  be  seen  from  the  explanation  accompanying 
Fig.  2. 


INDUSTRIAL  METHODS  OF  PURIFICATION 


FIG.  2    CONTINUOUS  WATER  PURIFICATION  APPARATUS.— -DODGE  MANUFACTURING  Co., 

MISHAWAKA,  INDIANA. 

A — Wood  fiber  filter  M — Reaction  chamber 

B' — Raw  water  inlet  tank  N — Spiral  accelerator  plates 

E — Overshot  water-wheel  P — Sludge  catchers 

G — Soda  ash  solution  tank  X — Gravity  overflow  of  treated  water 

J — Lime  saturating  tank  Y — Treated  water  reservoir 

S  and  P — Flushing  valves 


20 


THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


A.. 


FIG.  3    INTERMITTENT  PURIFICATION  SYSTEM,  AS  USED  BY  THE  CHICAGO  &  NORTH- 
WESTERN RY.  Co., — DEVISED  BY  G.  M.  DAVIDSON,  CHEMIST  AND 
ENGINEER  OF  TESTS,  C.  &  N-W.  RY.  Co. 

The  pump  house  is  located  between  two  tanks.  The  raw  water,  together  with 
the  chemical  mixture,  is  delivered  into  the  tilting  vessel,  "P",  from  which  it  is 
discharged  to  the  right  or  left  into  the  wooden  box  or  trough  "r"  and  "r1".  These 
troughs  are  provided  with  shut-off  gates,  so  that  the  treated  water  may  be  delivered 
entirely  into  one  tank  or  the  other. 


MIXING  AND  MEASURING  DEVICES 


21 


FIG.  4    CHEMICAL  MIXING  AND  MEASURING  DEVICE. 

The  chemical  is  delivered  through  the  funnel  "n",  together  with  the  raw  water, 
passing  through  the  pipe  "o"  into  the  tilting  vessel  "P". 

Designed  by  G.  M.  Davidson,  Chemist  and  Engineer  of  Tests,  Chicago  & 
Northwestern  Ry.  Co. 


22  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


FIG.  5     CHEMICAL  MIXING  AND  MEASURING  DEVICE. 

Showing  the  measuring  pump  "k",  which  it  actuated  by  walking  beam  attached 
to  shaft  "w",  discharging  the  measured  quantity  of  chemicals  through  the  pipe  "m" 
into  the  tilting  vessel  "p2".  The  standpipe  "z"  is  for  indicating  the  depth  of  the 
chemical  solution  remaining  in  tank  "d". 

Devised  by  G.  M.  Davidson,  Chemist  and  Engineer  of  Tests,  Chicago  &  North- 
western Ry.  Co. 


RATING  OF  BOILER  WATERS  23 

TABLE  IV 

RATING  OF  BOILER  WATERS 

As  made  use  of  by  the  .C.  B.  &  Q.  R.  R. 

W.  H.  Wichorst,  Engineer  of  Tests. 

Incrusting  Rating. 
The  figures  represent  parts  per  100,000 

1.  Very  Good — Water   having   sodium   carbonate,    and   hardness   less 

than  35. 

2.  Good  —Water  having  sodium  carbonate,  and  hardness  greater 

than  35. 

Water  having  sulphate  hardness  less  than  5,  or  total 

hardness  less  than  20. 

3.  Fair  —Water  with  sulphate  hardness  between  5  and  10,  and 

total  hardness  less  than  30,  or  total  hardness  between 
20  and  30. 

4.  Bad  —Water  with  sulphate  hardness  between  10  and  15,  and 

total  hardness  less  than  50,  or  total  hardness  between 
30  and  50. 

5.  Very  Bad  — Water  with  sulphate  hardness  greater  than  15,  or  total 

hardness  greater  than  50. 

Foaming  Rating. 

A.  Very  Good — Alkali  salts  less  than  7. 

B.  Good  — Alkali  salts  between     7  and  15. 

C.  Fair  —Alkali  salts  between  15  and  25. 

D.  Bad  —Alkali  salts  between  25  and  40. 

E.  Very  Bad  — Alkali  salts  over  40. 

Summary  of  Ratios: — In  the  preceding  discussion  the  various  scal- 
ing ingredients  have  all  been  reduced  to  the  CaC03  equivalent,  chiefly 
for  convenience  in  making  calculations  for  the  amount  of  reagent  needed 
in  treatment.  If,  however,  we  have  in  hand  the  analysis  of  a  water 
giving  the  hypothetical  combination  as  the  various  ingredients  are  sup- 
posed to  occur  in  the  water,  it  will  be  found  more  convenient  to  make 
use  of  a  table  of  factors,  as  given  below.  This,  in  the  main,  has  been 
compiled  from  the  Report  of  the  Committee  on  Water  Service  of  the 
American  Railway  Engineering  and  Maintenance  of  Way  Association, 
embodied  in  their  Bulletin  No.  83,  January,  1907.  See  also  ''The  Hard- 


THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


ness  of  Illinois  Municipal  Water  Supplies,"  by  Dr.  Bartow,  Proc.  Illi- 
nois Society  of  Engineers  and  Surveyors,  1909. 

TABLE  V 

SHOWING  THE  RATIO  OF  REAGENT  TO  INCRUSTING  MATERIAL  REQUIRED  FOR  WATER 

TREATMENT. 

Wt.  of  1  U.  S.  gallon  of  water  at  65°F 58,330  grains 

1  part  :  1,000,000  : :  x  :  58,330 
Hence,  x  grains  per  gallon  =  0.05833  X  parts  per  million. 


part  free  CO2  requires  1.27  parts  CaO 


Na2CO3 

0-53 

CaCOa 

"        0.36 

CaSO* 

0.78 

CaCl2 

0.96 

MgCOa 

1-33 

MgSO* 

0.88 

MgCl2 
acid   (HSSOO   " 


i.n 


0.57 


CaO 
CaO 

Na2CO3 

CaO 

Na2COs-fo.47 
pts.  CaO 

Na2CO3-fo.59 
pts.  CaO 

CaO+i.o8 
pts.  Na2CO3 


and  leaves  no  foaming  material 

"  i     part  " 

"  no     "  " 

"  1.04  " 

k         u  IQ5  «  « 

"  no     " 

"  1.18  "  " 

"  1.22  "  "  " 


Standards  for  indicating  Degrees  of  Hardness:  —  The  English,  de- 
grees of  hardness  on  Clark's  scale  as  it  is  usually  called,  represent  grains 
per  Imperial  gallon  ;  that  is,  each  degree  is  one  part  per  70,000.  Hence 

70  000 
1  degree  of  hardness  by  the  Clark  scale  would  be        '         or  1.2  de- 


grees  per  U.  S.  gallon. 

It  is  usual  in  this  country  to  refer  hardness  as  well  as  the  other 
values  to  parts  per  million,  although  the  French  unit  is  sometimes  used, 
wherein  the  reference  is  to  parts  per  100,000. 

TABLE  VI 
RELATIVE  VALUES  FOR  DEGREES  OF  HARDNESS 


Grains 

Grains 

French 

U.  S. 

per 
U.  S. 
gallon 

per 
Imperial 
gallon 

unit 
or  parts 
per  100,000 

unit  or 
parts  per 
1,000,000 

1  part  per  1,000,000 

0.058 

0.07 

0.10 

1.00 

1  degree 

Clark's  scale 

1.20 

1.00 

1.43 

14.30 

COMPOSITION  AND  TREATMENT  25 

Limits  of  Purification: — It  should  be  borne  in  mind  that  at  ordi- 
nary temperatures  the  precipitated  material  is  soluble  to  the  extent  of 
3  to  5  grains  per  gallon.  Hence,  this  represents  the  approximate  limit 
to  which  scaling  matter  can  be  removed.  At  higher  temperatures  the 
solubility,  especially  of  the  magnesium  product,  is  greatly  reduced.  So 
that,  if  it  were  practicable  to  raise  the  temperature  of  the  water  for 
treatment  50° F,  the  residual  scale  forming  material  could  be  reduced 
to  1  or  1.5  grains  per  gallon.* 

Typical  Waters  and  Their  Treatment: — In  the  Table  below  is  given 
the  composition  of  a  number  of  typical  waters  from  municipal  supplies 
in  Illinois,  together  with  the  calculated  amounts  of  the  reagents  called 
for  and  the  cost  of  the  same  calculated  on  the  basis  of  lime  at  $6.00  per 
ton  and  soda  ash  at  $6.00  per  100  pounds.** 

*"Water  Softening",  W.  A.  Powers,  Chief  Chemist,  Santa  Fe  Railway. 
**From  Hardness  of  Municipal  Water  Supplies.     Dr.  Bartow,  Proc.  111.  Soc. 
Engineers  and   Surveyors    1909. 


26  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


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CHAPTER   II 


FUEL 

Introduction: — Motion,  industrially  considered,  is  a  commodity 
which,  when  available  in  proper  form  and  in  sufficient  quantity,  is  des- 
ignated as  power. 

The  sources  of  motion  are  two  in  number : — 

(1)  Gravity 

(2)  Chemical  Action. 

Gravity  is  transformed  into  motion  through  the  medium  of  falling 
water,  and  to  a  smaller  extent  by  means  of  wind  currents. 

Chemical  activity  may  be  derived  from  the  world's  fuel  supply  in 
greater  amount  and  at  less  cost  than  from  any  other  source. 

By  the  burning  of  fuel,  chemical  action  may  be  made  to  transfer 
its  motion  through  the  medium  of  steam  or,  to  a  smaller  extent,  as  in 
the  internal  combustion  engine,  directly  and  without  any  medium,  to 
the  working  parts  of  machinery.  Proximity  to  fuel  beds,  therefore,  or 
accessibility  by  reason  of  shipping  facilities  is  an  index  of  present  or 
potential  activity  along  industrial  lines.  Hence,  it  is  evident  that  the 
fundamental  purpose  of  the  industrial  examination  of  fuels  is  to  cor- 
rectly measure  the  amount  of  chemically  active  material  which  resides 
in  a  given  sample.  This  may  be  determined  in  two  ways:  First,  by 
analytical  methods  wherein  the  amount  of  inorganic  or  chemically  in- 
active substance  is  determined,  as  distinct  from  the  organic  or  chemi- 
cally active  material;  and,  second,  by  actual  combustion  whereby  the 
fuel  is  made  to  indicate  its  activity  by  the  evolution  of  heat,  the  quantity 
of  which  may  be  measured. 

Types  of  Fuel: — For  convenience  in  discussion,  fuels  are  divided 
into  solid,  liquid,  and  gaseous  types.  This  classification  with  further 
subdivisions  may  be  shown  in  tabulated  form  as  follows: 

fWood 
Solid  -I  Coke  and  Charcoal 


FUELS  4 


Liquid 


[Coal 

[Alcohol 
j  Distillates 
[Petroleum 


fNatural  Gas 
Gaseous      J  House  Gas 

[Producer  Gas 

Wood: — By  reason  of  the  high  cost  of  wood  it  is  rapidly  passing 
out  of  the  list  of  available  fuels.  While  its  content  of  inactive  substance 
in  the  form  of  ash  is  low,  its  content  of  free  moisture  is  high,  even  in 

27 


28  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

seasoned  wood,  and  together  with  combined  water  constitutes  more  than 
half  of  the  wood  by  weight.  Its  activity,  therefore,  measured  as  heat 
is  only  about  half  that  of  good  coal  averaging  6,000  or  7,000  British 
thermal  units  per  pound.  Since  a  cord  of  hard  wood  weighs  approxi- 
mately 4,000  pounds,  that  amount  is  about  equal  in  heat  value  to  a  ton 
of  coal. 

Coke: — Coke  is  at  present  chiefly  a  fuel  having  special  properties 
which  make  it  suitable  for  metallurgical  purposes.  It  has  very  little 
inactive  material  except  the  ash,  which  is  always  of  higher  percentage 
than  in  the  coal  from  which  it  is  made.  Measured  in  terms  of  heat 
units,  coke  is  equal  to  the  average  anthracite  coal. 

Coal: — Coal  is  by  far  the  most  abundant  and  cheapest  of  all  fuels. 
It  varies  in  character  from  the  hard,  rock-like  anthracites  to  the  soft 
lignites.  The  inert  non-active  substances  in  the  form  of  water  and  ash 
vary  from  8  per  cent  to  40  per  cent,  and  are  inversely  related  to  the 
quantity  of  heat  available.  Since  these  factors  are  fundamental  in  the 
commercial  estimation  of  values,  classification,  etc.,  of  coal,  they  will  be 
discussed  under  the  more  general  treatment  of  coal  which  is  taken  up 
later. 

Alcohol: — Alcohol  is  a  prospective  rather  than  a  present  source  of 
fuel  energy.  It  has  no  ash  but  a  large  percentage  (34.8%  of  combined 
oxygen,  which  approximately  represents  the  inert  material.  Its  heat 
value  in  pure  form  is  12,391  B.t.u.  per  pound.  It  is  denatured  usually 
by  adding  about  one-third  of  one  per  cent  of  kerosene  to  render  it  un- 
palatable and  approximately  ten  per  cent  of  methyl  or  wood  alcohol  to 
make  it  poisonous  and  not  easily  purified  by  redistilling.  About  ten 
per  cent  of  water  is  usually  added  for  use  in  gas  engines.  Other  per- 
missible formulas  are  given  in  United  States  Department  of  Agricul- 
ture, Bureau  of  Chemistry  Bulletin  No.  130. 

Distillates: — The  petroleum  distillates  are  hydro-carbon  compounds 
and  are  almost  entirely  free  from  inactive  material.  Their  heat  value 
varies  with  the  specific  gravity,  which  directly  is  a  measure  of  the  ratio 
of  carbon  to  hydrogen.  The  lighter  the  distillate  the  higher  the  ratio 
of  hydrogen  and,  consequently,  the  higher  the  heat  value,  which  may 
vary  from  19,000  to  22,000  B.t.u.  per  pound. 

Petroleum: — Chemically  considered,  petroleum  is  substantially  the 
same  as  distillates  but,  being  heavier,  has  a  lower  heat  value,  ranging 
from  18,000  to  20,000  B.t.u.  per  pound.  Crude  petroleum  varies  in 
character,  some  districts  yielding  heavier  and  some  lighter  oils.  Petro- 
leum residues  have  had  the  lighter  oils  removed  by  distillation.  These 
residues  are  of  higher  specific  gravity  and  lower  heat  value. 

Gases: — Gases  are  more  or  less  mixed  with  inert  material  and,  when 
measured  with  reference  to  their  chemical  activity  in  the  form  of  heat, 


FUEL  RESOURCES 


29 


the  values  are  referred  to  a  cubic  foot  at  60° F.  temperature  and  a 
pressure  of  30  inches  of  mercury,  as  representing  the  average  or  stand- 
ard temperature  and  pressure  of  the  atmosphere.  Because  of  the  inev- 
itable tendency  for  all  forms  of  this  material  to  have  an  admixture  of  in- 
ert gases,  the  heat  values  are  very  variable.  Their  character  may,  how- 
ever, be  expressed  in  a  general  way  as  follows : 

Natural  Gas  is  usually  composed  in  large  part  of  methane  or  marsh 
gas,  which  in  pure  form  has  a  value  of  1010  B.t.u.  per  cubic  foot  at  the 
above  temperature  and  pressure. 

House  Gas  in  the  majority  of  cities  in  the  United  States  is  required 
to  have  a  heat  value  not  less  than  600  B.t.u.  per  cu.  ft. 

Producer  Gas  may  vary  from  350  to  400  units  in  the  richer  form 
to  125  units  as  in  the  "suction"  gas  producer,  and  to  as  low  as  90  units 
per  cubic  foot  in  the  gases  from  the  blast  furnace,  which  may  be  looked 
upon  as  a  special  type  of  gas  producer. 


o 

o 
o 

CM 
I 
(0 

I 

L. 

O 


o 

1 


1880    1885     1890     1895     1900     1905      1910      1915      1920 

600  i  i  i  i  i  i  i  i  i  i  i  i  i  i  i  i  i  i  i  i i  i  i  i  i  i  i  i  i  i  i  i  i  i  M  600 


500 


200 


100 


100 


1380    1885     1890     1895     1900     1905      1910      1915      1920 

ANNUAL  PRODUCTION  OF  COAL 
IN  THE  UNITED  STATES,  1880  TO  1914 

COAL 

Introduction: — Of  all  the  fuel  supplies  available,  coal  constitutes 
by  far  the  largest  part.  Our  chief  consideration,  therefore,  will  be 
given  to  that  topic.  The  annual  output  of  coal  in  the  United  States 
for  the  year  1914  was  422,329,000  tons.  A  chart  of  the  production  by 
years  is  of  interest  as  furnishing  an  index  of  industrial  activity.  A 
suggestion  also  is  furnished  as  to  the  possibility  of  ultimate  exhaustion 


THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


of  this  source  of  fuel  supply,  and  the  necessity  of  developing  the  highest 
possible  efficiencies  in  its  use. 

Classification: — The  classification  of  coal  in  common  use  was  out- 
lined by  Frazer*  in  1877  and  was  based  on  his  study  of  the  coals  of 
Pennsylvania.  A  wider  knowledge  of  the  character  of  western  and  mid- 
continental  deposits  calls  for  the  addition  of  a  few  subdivisions.  In 
tabular  form  the  following  classification  based  on  that  of  Frazer  most 
nearly  approaches  everyday  usage: 

[  Anthracites,  Volatile  matter,  below  5% 


Semi-anthracites, 

Semi-bituminous, 
(Pocahontas) 


COALS  «! 


Bituminous, 


Black  Lignites, 
or  sub-Bituminous 


Vol.,  5—10% 
Vol.,  15—22% 


Eastern,  Vol.,  25—35% 

Vein  Moist.,  2—4% 

Mid-Continental, 

Vol.,  35—45% 
Vein  Moist.,  6—17% 

Vol.,  35—45% 
Vein  Moist.,  17—20% 


Vol.,  25—45% 

Brown  Lignites,  Vein  Moist.,  20 — 25% 

Numerous  systems  of  classification  have  been  proposed,  but  none 
has  been  received  with  sufficient  unanimity  to  warrant  its  general  adop- 
tion. In  the  main,  they  are  based  on  certain  ratios  which  have  come 
to  be  designated  by  technical  terms  as  follows : — 

Fuel  Ratio: — A  term  originaly  proposed  by  Frazer  is  represented 

by  the  fixed  carbon  divided  by  the  volatile  matter:   '  Since 

Vol.  M. 

this  ratio  is  highest  in  the  anthracites  and  semi-anthracites,  and  lowest 
in  the  lignites,  it  serves  in  a  general  way  as  an  indication  of  the  type 
of  coal  as  well  as  its  behavior  under  conditions  of  combustion. 

Carbon-Hydrogen  Ratio: — This  term  was  proposed  by  Campbell* 
and  represents  the  percentage  of  total  carbon,  divided  by  the  percent- 

T    C 
age  of  total  hydrogen,     -g-      These  factors  are  obtained  by  ultimate 

*Trans.  Am.  Inst.  Min.  Eng.  6,  p.  430.     (1877-8.) 
**U.  S.  Geo.  Survey  Professional  Paper  No.  48,  Pt.  I,  p.  168. 


COAL  ANALYSIS  31 

analysis  and  are  not  usually  available.  Unfortunately  also  the  hydro- 
gen factor  used  by  Campbell  was  the  total  hydrogen  of  the  coal  and 
also  of  the  free  moisture  which  may  have  happened  to  be  present  at  the 
time  of  analysis.  As  this  constituent  is  variable  and  does  not  govern 
either  the  geological  or  chemical  characteristics  of  the  coal  it  should  not 
be  a  contributing  element  in  the  carbon-hydrogen  ratio. 

The  Carbon  Ratio*  represents  the  volatile  carbon,  (that  is,  the 
carbon  joined  with  hydrogen  or  other  elements  to  admit  of  its  assuming 
a  volatile  form)  divided  by  the  total  carbon  content  of  the  coal  and 
this  multiplied  by  100  gives  directly  the  percent  the  volatile  carbon  is 
of  the  total  carbon.  The  advantage  of  this  ratio  is  the  fact  that  it 
remains  the  same  whether  the  moisture  and  ash  are  present  or  absent, 
thus  eliminating  some  of  the  most  serious  variables  inherent  in  many 
of  the  proposed  schemes  of  classification.** 

ANALYSIS  OP  COAL 

Methods: — Coal  may  be  subjected  to  either  the  ultimate  or  proxi- 
mate method  of  analysis.  In  the  former,  beside  the  moisture,  ash,  and 
sulphur  factors,  a  determination  is  made  of  the  constituent  elements 
comprising  the  organic  substance  of  the  coal-;  namely,  carbon,  hydro- 
gen, nitrogen,  and  oxygen. 

In  the  proximate  method,  besides  the  moisture,  ash,  and  sulphur, 
there  are  determined,  instead  of  the  elemental  substances  of  the  organic 
part,  only  volatile  matter  and  fixed  carbon.  The  ultimate  analysis 
furnishes  data  from  which  the  heat  value  of  the  coal  can  be  calculated. 
The  proximate  analysis  gives  the  necessary  data  for  judging  of  the 
kind  and  general  character  of  the  coal.  It  is  the  proximate  method 
only  which  will  be  here  considered,  the  main  object  being  to  discuss 
the  significance  of  the  various  factors,  methods  of  calculation,  etc.  The 

*Parr,  S.  W.,  The  classification  of  coals :  J.  A.  C.  S.,  Vol.  28,  1906,  p.  1425. 
**A   brief   bibliography   of    discussions   upon    coal   classification   is   given    as 
follows : — 

Johnson,    W.    R.,    Report    to    United    States     Government    on     "American 

Coals,"   1844. 
Ure's  Dictionary,  1845. 

Frazer,  Persifer,  Jr.,  Trans.  Min.  Eng.,  Vol.  6,  1878,  p.  430. 
Watt's  Dictionary  of  Chemistry,  Vol.  i,  p.  1032. 

Rogers,  H.  D.,  Report  to  English  Government,  Vol.  2,  Pt.  2,  p.  983. 
U.  S.  G.  S.  Professional  Paper  No.  48. 
Parr,  S.  W.,  Jour.  Am.  Chem.  Soc.,  Vol.  28,  p.  1425. 
Campbell,  M.  R.,  A.  I.  M.  E.,  Vol.  36,  p.  324- 
Grout,  F.  F.,  Economic  Geology,  1907,  p.  226. 
White,  David,  U.  S.  G.  S.  Bulletin  No.  382. 


32  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC 

analytical  methods  are  taken  up  elsewhere  under  the  directions  for  the 
laboratory  processes. 

SAMPLING 

Introduction: — Samples  may  be   taken  by  different  methods  and 
for  a  variety  of  purposes.     Three  kinds  are  generally  recognized: 
1 — Hand  Samples 
2 — Face  Samples 
3 — Commercial  Samples 

Hand  Samples: — As  the  name  implies,  hand  samples  are  taken  in 
small  amounts  and  the  entire  sample  is  submitted  for  inspection  and 
analysis.  In  the  nature  of  the  case  such  samples  are  selected  and  are 
not  representative  of  the  mass  from  which  they  come.  Their  analysis 
may  be  of  interest  to  the  person  collecting  them  but  the  results  are 
utterly  without  commercial  value  or  significance. 

Face  Samples: — This  term  is  applied  to  samples  taken  at  the  work- 
ing face  of  a  coal  seam.  They  are  essential  for  purposes  of  scientific 
study  and  serve  as  a  basis  for  determining  the  changes  that  occur  in 
the  process  of  mining,  transportation  and  storage.  The  taking  of  such 
samples  is  not  different  in  principle  from  the  taking  of  commercial 
samples.  The  chief  essential  is  a  kit  of  the  knock-down  type,  not  too 
heavy  for  packing  and  not  too  tedious  in  setting  up  and  operating. 
Specific  details  are  not  given  here.* 

Commercial  Samples: — The  majority  of  samples  are  taekn  in  con- 
nection with  industrial  operations,  in  the  process  of  coal  inspection, 
control  of  contracts,  determination  of  efficiencies,  etc.,  and  involves  the 
sampling  of  wagon  loads,  car  lots,  barge  shipments  and  masses  in  stor- 
age. The  general  principles  under  any  of  these  conditions  are  the  same. 
The  important  features  to  be  observed  are  given  special  emphasis  as 
follows : — 

COMMERCIAL  SAMPLING** 

Necessity  of  Care: — Without  question,  the  critical  point  in  the  en- 
tire range  of  coal  inspection  and  analysis  is  in  the  sampling.  If  the 
sample  taken  is  truly  representative  of  the  entire  lot,  the  results,  if 
accurate  in  themselves,  furnish  correct  information  as  to  the  larger 
mass  of  which  the  sample  is  a  part.  If,  on  the  other  hand,  the  sample 
is  in  error,  the  results  of  the  analysis  though  correct  in  themselves  will 
be  in  error  so  far  as  they  relate  to  the  mass  under  consideration. 
Throughout  the  process  of  sampling  two  points  must  be  observed  with 
scrupulous  care : 

*See  Bulletin  No.  29,  111.  State  Geol.  Surv.,  p.  17. 

**Adapted  from  111.  State  Geol.  Surv.  Bulletin  No.  29.     Purchase  and  Sale  of 
Illinois  Coal  on  Specification.     By  S.  W.  Parr.     (1914.) 


SAMPLING  OF  COAL  33 

First — The  sample  taken  must  be  representative  of  the  whole,  that 
is,  the  distribution  of  the  various  substances  which  go  to  make  up  the 
original  mass  must  be  maintained  without  any  change  in  the  relative 
amount  of  *  the  various  constituents. 

Second — The  moisture  content,  which  changes  readily,  must  be 
under  exact  control  so  that  at  any  stage  the  ratio  of  moisture  present 
to  the  original  moisture  of  the  mass  may  be  definitely  known. 

Material  to  Be  Taken: — As  stated  above,  the  first  essential  in  a 
sample  is  that  it  shall  truly  represent  the  mass  of  which  it  is  a  part. 
To  secure  this  result  a  few  fundamental  conditions  must  be  observed, 
as  follows: 

The  gross  sample  must  be  representative  of  the  various  kinds  of 
material  present.  That  is  to  say,  a  mass  of  coal  consists  of  fine  stuff, 
lump,  bone,  slate,  pyrites,  and  other  constituents.  As  a  rule  the  "fines" 
differ  in  composition  from  the  lump,  hence  the  sample  must  have  these 
two  sorts  of  material  in  their  proper  proportion.  The  same  is  even 
more  true  of  slate  or  pyrites,  of  which  the  composition  differs  so  widely 
from  that  of  the  major  part  of  the  mass.  An  undue  amount  of  such 
material  would  cause  a  serious  disturbance  in  the  accuracy  of  the 
sample.  . 

Amount: — In  procuring  a  representative  sample  a  large  element 
of  safety  resides  in  the  quantity  taken.  In  general,  the  larger  the 
amount,  the  more  representative  it  will  be.  However,  conditions  differ. 
It  is  easier,  for  example,  to  procure  an  even  sample  from  the  face  of  a 
working  vein  or  from  a  carload  of  screenings  than  from  a  carload  or 
other  mass  of  lump  or  run-of-mine  coal.  In  the  latter  case  larger 
amounts  should  be  taken  than  in  the  former. 

The  limits  of  practicability  for  the  proper  handling  of  the  sample 
must  however  be  considered.  In  general,  the  gross  sample  should 
weigh  ^approximately  from  200  to  600  pounds.  Doubtless  200  pounds 
of  screenings,  taken  with  fairly  good  distribution  throughout  the  un- 
loading of  a  40-  or  50-ton  car,  will  yield  a  very  true  sample.  The  diffi- 
culties increase  greatly  with  the  increase  of  the  size  of  the  particles, 
as  in  the  case  of  lump  or  mine-run  coal.  If  mechanical  appliances  for 
grinding  are  available,  the  larger  amount  should  be  taken,  but  a  smaller 
sample  well  crushed  down  before  quartering  is  better  than  a  greater 
mass  quartered  down  while  the  particles  are  still  in  larger  pieces. 

Ratio  of  Size  to  Mass: — Assuming  that  the  sample  as  taken  is  made 
up  of  the  various  kinds  of  material  in  proper 'proportion,  the  next  im- 
portant item  is  to  maintain  these  variables  in  their  ratios  throughout 
the  process  of  reducing  the  gross  amount  to  a  small  working  or  labora- 
tory sample.  To  insure  this  result,  there  must  be  maintained  a  certain 
ratio  of  size  of  the  particles  to  size  or  weight  of  the  mass.  This,  as  a 


34 


THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


rule,  is  based  on  a  formula  which  provides  that  the  weight  of  the  largest 
piece  of  impurity  shall  have  a  ratio  to  the  weight  of  the  mass  of  about 
2:  10,000.  For  example,  a  mass  weighing  10,000  grams,  or  about  22 
pounds,  should  contain  no  particles  weighing  more  than  2  grams.  This 
would  mean  that  the  largest  particle,  as  for  example,  a  piece  of  iron 
pyrites,  must  not  be  over  1/4  inch  in  its  greatest  diameter. 

The  final  ratio  of  sizes,  however,  should  be  determined  by  the  meth- 
ods available  for  grinding.  With  mechanical  appliances  for  obtaining 
the  smaller  sizes,  a  table  of  ratios  with  greater  safety  limits  can  be 
adopted  than  is  perhaps  practicable  where  the  crushing  is  done  by  hand. 
If  a  power  crusher  is  available,  the  entire  sample  should  be  passed 
through  the  mill  and  reduced  to  a  size  which  will  pass  a  ^-ineh  screen. 
If  the  crushing  must  be  done  by  hand,  the  first  reduction  in  size  of  the 
particles  should  be  such  that  the  entire  mass  will  pass  through  a  1-inch 
screen.  When  by  quartering,  the  sample  is  reduced  to  100  pounds,  the 
size  of  the  particles  should  be  further  reduced  to  a  size  that  will  pass  a 
i/2-inch  screen,  and  with  a  50-pound  sample  in  hand  the  crushing  should 
be  carried  to  y^-ineh  mesh.  The  subdivisions  with  their  respective  sizes 
are  shown  in  tabular  form  as  follows: 

TABLE  VIII 
SIZE  OF  MESH  FOR  DIFFERENT  SUBDIVISIONS  OF  SAMPLE 


Weight  of   subdivisions   of   sample 
(pounds) 


Size  of  mesh  to  which  each  subdivision 
should  be  broken   (inches) 


500 

250 

125 

60 

30 


Illinois  coals  are  easily  crushed  in  mills  which  are  available  at  little 
expense.  Hence  it  is  entirely  reasonable  to  require  that  gross  samples, 
when  reduced  in  mass  to  50  or  75  pounds,  shall  be  passed  through  a  mill 
set  for  grinding  to  approximately  1/8  inch.  For  this  work,  a  mill  which 
is  not  of  the  jaw-crusher  or  roller  type  is  preferred,  since  these  types 
produce  too  large  a  percentage  of  fine  material,  and  the  harder  pieces  of 
slate,  especially  those  of  flaky  or  plate-like  structure,  are  liable  to  pass 
in  pieces  having  inadmissably  large  dimensions  in  two  directions,  even 
though  the  adjustment  used  would  seem  to  be  fine  enough  to  prevent  the 
passage  of  such  material.  A  grinder  of  the  coffee-mill  type  or  one  with 
projecting  teeth  on  the  grinding  surfaces  will  be  found  to  produce  a 
more  uniform  size  and  the  minimum  amount  of  dust.  The  grinding 
surfaces  of  such  a  machine  are  shown  in  figure  6,  and  the  same  type  of 
mill  is  shown  set  up  in  figure  7. 


METHODS  OF  GRINDING 


35 


Figure  6 — GRINDING  SURFACES  OF  COAL  CRUSHER 


Figure  / — COAL  GRINDER  OF  THE  COFFEE-MILL  TYPE 

Weight  about  16  pounds.    Readily  knocked  down  for  packing.    Especially  Designed 
for  use  in  taking  Face  Samples. 

Mixing  and  Subdividing: — As  a  further  precaution  in  maintaining  a 
correct  distribution  of  the  various  constituents,  emphasis  is  placed  upon 


36  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


the  necessity  of  thorough  mixing,  followed  by  even  selection  of  the  re- 
maining sub-divisions.  It  is  true  that  fine  grinding  contributes  mate- 
rially to  this  end  but  further  care  is  necessary.  It  is  entirely  practicable 
to  mix  a  50-pound  sample,  ground  as  above  described,  by  rolling  in  an 
oilcloth  about  five  feet  square.  This  is  accomplished  by  taking  one  corner 
of  the  cloth  and  carrying  it  over  the  pile  towards  the  diagonally  oppo- 
site corner  so  as  to  cause  the  mass  to  roll  over  upon  itself,  then  reversing 
the  motion  and  repeating  the  process  with  the  other  two  corners.  Fif- 
teen or  twenty  such  alterations,  depending  somewhat  upon  the  size  of  the 
sample,  should  be  sufficient  to  effect  an  even  mixture.  Where  available, 
however,  especially  in  commercial  sampling,  a  mixer  is  to  be  preferred. 
Such  a  device  is  most  conveniently  made  in  the  form  of  a  drum  having 
cone-shaped  ends  capable  of  being  closed  air-tight,  and  mounted  so  as  to 
revolve  endwise. 

The  subdividing  of  the  larger  sample,  to  reduce  it  to  a  convenient 
size  for  transmission  to  the  laboratory,  requires  special  consideration  as 
having  an  important  bearing  on  the  maintenance  of  the  correct  ratio  of 
constituents.  This  may  be  best  shown  by  the  data  given  in  Table  IX. 

TABLE  IX 
ASH  VARIATIONS  IN  DIFFERENT  SIZES  OBTAINED  FROM  DUPLICATE  3-PouND  SAMPLES 


Series 

Mesh 

Dupli- 
cate 
halves 

Per  cent 
of  each 
size 

CO2  in 
"dry 
coal" 

Ash  cor- 
rected for 
CO2  in  "dry 
coal 

a  and  b  compos- 
ited by  calcula- 
tion 

ii 

On  20 

a 
b 

41.7 
48.4 

.40 
•37 

14.11 
14.00 

I2 

Through  20 
On  60 

a 
b 

41.7 
37-9 

.85 

1.  00 

iS-55 
15.42 

a  16.32 

b              15.86 

I3 

Through  60 

a 

16.6 

1.31 

23-89 

b 

13-7 

1.38 

23-65 

Average  16.09 

2i 

On  20 

a 
b 

29.1 
25.0 

•53 
.46 

I5-9I 
15-68 

2_> 

Through  20 
On  60 

a 
b 

48.4 
51-9 

•94 
.98 

16.23 
1  6.06 

a  17.90 

b             17.80 

23 

Through  60 

a 
b 

22.5 
23.1 

1.32 
1.28 

24.09 
23.98 

Average  17.85 

THE  RIFFLE 


37 


Note  in  this  table  that  series  1  and  2  are  3-pound  samples  taken  by 
subdividing  in  the  same  manner  the  same  gross  sample  of  about  30 
pounds.  Each  sample  was  ground  to  8-mesh  and  sized.  It  will  be  seen 
that  in  series  1,  duplicates  a  and  b  had  16.6  and  13.7  per  cent  of  the  60- 
mesh  size,  whereas  in  series  2  the  duplicates  a  and  b  had  22.5  and  23.1 
per  cent  respectively.  Note  further  the  great  increase  in  ash  in  the  fine 
size  as  compared  with  the  ash  in  the  coarse  material.  For  example, 
series  1  having  an  average  of  14  per  cent  of  ash  in  the  coarse  size  has 
an  average  of  23.75  per  cent  in  the  fine  portion.  A  similar  increase  in 
ash  is  seen  in  the  corresponding  sizes  in  series  2.  The  ultimate  ash 
average  for  series  1  is  16.09  per  cent  and  for  series  2  it  is  17.85  per  cent. 


Figure  8 — RIFFLE 

These  values  vary  consistently  with  the  variation  in  the  percentages  of 
fine  material  in  the  respective  series.  On  the  other  hand,  the  duplicate 
halves  a  and  b  throughout,  because  of  their  uniformity  resulting  from 
the  sizing  process,  show  results  in  the  several  pairs  which  check  very 
closely. 

The  values  as  presented  in  the  table,  therefore,  show  clearly  that 
in  the  process  of  subdividing  the  gross  sample  and  in  the  further  reduc- 
tion of  the  sample  as  received  at  the  laboratory,  great  care  must  be  exer- 


38  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

cised  to  see  that  no  part  of  the  manipulation  is  of  such  a  nature  as  will 
promote  segregation  of  the  constituents. 

A  riffle  constructed  according  to  the  pattern  shown  in  figure  8  may  be 
used  to  advantage  after  the  sample  has  been  reduced  by  quartering  to 
about  30  pounds.  At  this  stage  the  sample  is  ground  to  1/8-inch  size, 
hence  the  riffle  openings  may  be  1/2-inch  in  width.  With  this  variation 
in  the  openings  the  riffle  as  shown  in  fiure  8  is  substantially  the  one  de- 
scribed in  the  Bulletin  of  the  Ohio  Geological  Survey,  No.  9,  p.  313,  1908. 

Moisture  Control: — The  second  essential  in  taking  and  preparing  a 
sample  relates  to  the  free  moisture  present,  and  requires  that  the  changes 
in  moisture  content ' '  must  be  under  exact  control  so  that  at  any  stage  the 
ratio  of  the  moisture  present  to  the  original  moisture  of  the  mass  may  be 
definitely  known.'' 

Loss  of  Moisture : — In  coals  of  this  region  especially,  where  the  mois- 
ture in  the  coal  as  it  comes  from  the  mine  averages  from  10  to  15  per  cent 
the  tendency  toward  moisture  changes  is  very  marked.  For  example,  the 
process  of  crushing  down  the  larger  sizes  affords  an  opportunity  for  the 
escape  of  moisture.  Again,  if  the  coal  is  spread  out  on  the  floor  of  a  hot 
boiler  room  or  left  exposed  to  currents  of  air  for  any  length  of  time  there 
will  be  a  serious  change  in  the  moisture  factor.  Another  practice  some- 
times followed  is  that  of  assembling  the  various  increments  of  the  gross 
sample  in  a  sack  or  other  receptacle  permitting  a  relatively  free  trans- 
mission of  air.  Samples  kept  in  this  manner  for  any  length  of  time  or 
shipped  in  such  containers  will  have  a  moisture  content  quite  different 
from  the  original. 

Precautionary  Measures: — The  methods  employed,  therefore,  in  col- 
lecting and  reducing  a  gross  sample  must  have  special  reference  to  this 
tendency  on  the  part  of  the  free  moisture  to  escape.  The  work  should  be 
done  rapidly  in  a  room  at  or  below  the  normal  temperature  and,  so  far  as 
possible^  with  the  use  of  closed  apparatus  which  admits  of  the  least  pos- 
sible exchange  of  the  contained  air.  Precautionary  measures  of  this  sort 
should  be  made  at  the  very  outset.  The  gross  sample,  which  is  made  up 
of  small  increments  collected  usually  over  a  considerable  length  of  time, 
should  be  enclosed  in  a  tight  box  or  clean  garbage  can  having  a  tightly 
fitting  cover  which  can  be  closed  and  locked  against  the  possibility  of 
change  until  the  time  for  grinding  and  reducing. 

Sampling  a  Car  Load : — A  car  of  coal  may  be  sampled  to  the  best  ad- 
vantage in  the  process  of  unloading.  An  occasional  half  shovelful  should 
be  thrown  into  a  proper  receptacle  so  that  by  the  time  the  car  is  unloaded 
approximately  200  pounds,  evenly  distributed  throughout  the  load  will 
have  been  taken.  This  will  mean  about  one-half  shovelful  for  every 
ten  full  scoops.  They  are  best  taken  in  the  process  of  shoveling  from 
the  bottom  of  the  car,  since  the  top  coal  rolls  down  and  mixes  fairly 


COMPOSITE  SAMPLES  39 

evenly  with  the  bottom.  It  should  be  kept  in  mind  that  in  taking  a 
sample  there  must  be  obtained  the  different  sizes  of  coal,  fine  and  coarse 
in  their  proper  proportions  from  the  entire  cross-section  of  the  mass,  and 
also  an  even  distribution  of  the  sample  lengthwise  of  the  car.  Even 
greater  care  must  be  taken  to  guard  against  loss  of  moisture  in  the  pro- 
cess of  collecting  and  in  reducing  the  gross  sample  for  the  reason  that  as 
a  rule  the  relative  humidity  outside  of  the  mine  is  lower  and  the  ten- 
dency of  the  moisture  to  leave  the  coal  is  correspondingly  increased. 

Sampling  the  Car  Without  Unloading: — It  has  been  shown  in  Table 
IX,  that  the  finer  particles  of  a  coal  mass  are  higher  in  ash  and  hence 
have  a  greater  specific  gravity.  They  are  therefore  more  likely  to  sep- 
arate by  gravity  from  the  coarser  material.  On  this  account,  if  a  car  is 
to  be  sampled  without  unloading,  it  is  necessary  to  dig  well  toward  the 
bottom  in  order  to  obtain  a  representative  sample.  Three  trenches  should 
be  dug  crosswise  of  the  load,  one  near  each  end  and  one  near  the  middle 
of  the  car.  These  trenches  should  go  down  nearly  to  the  bottom  of  the 
mass  and  each  size  be  taken  as  nearly  as  possible  in  its  proper  propor- 
tion. Lump  and  run-of-mine  lots  are  much  more  difficult  to  sample 
than  screenings,  but  it  should  be  noted  that  screenings  may  vary  greatly, 
for  not  infrequently  a  car  is  partially  loaded  from  one  bin  and  finished 
from  another  which  may  be  of  a  different  size  and  composition.  After 
obtaining  the  gross  sample,  the  methods  to  be  followed  are  the  same  as 
those  already  given. 

Composite  Samples: — It  is  often  desirable  to  composite  a  number 
of  samples.  In  this  way  a  single  sample  may  be  made  to  represent  a 
much  larger  quantity  of  coal  and  thus  cut  down  the  time  and  expense 
involved  in  procuring  the  analytical  data.  In  this  procedure,  however, 
it  must  be  remembered  that  even  greater  care  should  be  exercised  in  tak- 
ing the  several  component  samples.  The  amount  of  each  sample  enter- 
ing into  the  composite  must  be  in  proportion  to  the  mass  which  it  repre- 
sents, and  finally  a  thorough  and  positive  mixing  of  the  composited  mass 
must  be  effected  before  riffiing  down  the  same  to  the  usual  5-pound 
quantity. 

It  is  convenient  to  determine  the  amount  of  each  sample  to  be  taken 
by  employing  an  aliquot  system  of  weights.  For  illustration :  Suppose 
we  adopt  1  gram  to  the  100  pounds  as  the  unit  which  shall  enter  into 
the  composite.  Then  a  100,000-pound  car  of  coal  should  be  represented 
by  1,000  grams.  In  compositing,  therefore,  the  entire  content  of  each 
can  will  not  be  taken,  but  instead  an  aliquot  proportion  which  will  give 
to  each  car  lot  its  due  amount.  It  is  preferable  to  use  such  a  factor  as 
shall  utilize  the  major  part  of  the  several  5-pound  samples.  In  this  way 
the  gross  composite  from  10  cars  would  aggregate  20  or  30  pounds  in 
weight.  It  should  be  put  into  the  mixer  and  revolved  until  a  thoroughly 


40  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

homogeneous  mass  is  obtained  and  then  riffled  down  to  a  5-pound  sam- 
ple as  already  described.  For  this  procedure  it  is  obvious  that  the  nec- 
essary data  should  accompany  the  various  samples.  A  ticket  inserted  in 
the  can  before  sealing  should  give  the  data  needed. 

Mechanical  Sampling: — Numerous  attempts  have  been  made  to  de- 


Fig.  9.     Sample  Grinder.     Sturtevant  Mill  Company,  Boston,  Mass. 

vise  a  mechanical  method  for  taking  samples.  While  it  is  possible,  by 
such  means  to  eliminate  the  personal  equation,  it  is  difficult  to  avoid  seg- 
regation or  an  uneven  distribution  of  coarse  and  fine  material.  In  the 
sample  grinder  illustrated  in  Fig.  9,  there  is  an  evident  advantage  that 


SAMPLE  GRINDER  41 

with  a  power  grinder  larger  samples  may  be  handled,  thus  dividing 
rather  than  multiplying  the  errors.  Fig.  10  shows  the  method  of  open- 
ing up  and  cleaning  the  grinder  at  the  end  of  the  operation.  Both  the 
central  grinding  cone  and  the  wing  stirrer  underneath  may  be  lifted  out 
for  cleaning  the  entire  grinding  and  distributing  chamber.  The  samp- 
ling feature  is  so  arranged  that  an  aliquot  part,  approximately  10  per 


Fig.  10.     Grinder  Opened  for  Cleaning 

cent,  is  delivered  into  the  small  receptacle  in  the  process  of  grinding  the 
original  mass.  In  use  of  such  a  sample  grinder,  the  facility  with  which 
the  material  may  be  passed  through  makes  it  possible  to  take  much 
larger  initial  samples.  For  example,  if  occasional  shovelfuls  are  taken, 
well  distributed  throughout  the  unloading  of  a  car  in  such  an  amount  as 
to  yield  say  40  pounds  in  the  aliquot  portion,  then  it  is  known  that  ap- 


42  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


proximately  a  400-pound  gross  sample  has  been  passed  through  the 
grinder. 

Accuracy  of  the  Device: — Doubtless  the  best  method  for  determin- 
ing the  accuracy  of  the  sample  delivered  by  the  apparatus  is  to  compare 
the  ash  values,  water  free  basis,  as  obtained  from  the  small  sample  with 
the  ash  value  from  the  main  portion,  sampled  by  carefully  quartering 
down  by  hand  in  the  usual  manner.  A  number  of  tests  of  this  sort  are 
shown  in  the  Table  No.  X. 

TABLE  X 

ACCURACY  OF  SAMPLE  GRINDER 

Comparison  of  A$h  Values.    Dry  Basis 

Samples  A  and  B  obtained  from  Main  Portion  by  Quartering  and  Riffling. 


Ash  in 

A 

B 

Labora- 

small 

Ash  in  main   , 

Ash  in  main 

Coal 

sample  as 

portion 

portion. 

Number 

delivered 
by  grinder 

sampled  by 
quartering 

Duplicate  of 
A  :  —  Opposite 

and    riffling 

quarter 

8661 

Vermilion  Co. 

15-53 

15.22 

15.72 

Screenings 

8664 

Vermilion  Co. 

14.52 

14.52 

14.65 

Screenings 

• 

8667 

Vermilion  Co. 

19.19 

19.88 

19.72 

Screenings 

8670 

Vermilion  Co. 

1743 

17.78 

I/.58 

Screenings 

Another  test  has  been  applied  as  follows :  The  samples  as  obtained 
in  the  process  of  grinding  10  gross  samples  were  delivered  into  a  com- 
mon receptacle  in  their  proper  proportions  for  compositing.  Without 
further  mixing,  the  mass  of  approximately  40  pounds  was  poured  into 
the  grinder.  The  accuracy  of  the  small  sample  thus  obtained  was  de- 
termined as  before,  by  comparison  of  ash,  values.  The  main  portion  was 
sampled  again  by  pouring  through  the  mill  a  second  time  for  a  duplicate 
aliquot  delivery.  The  results  are  shown  in  Table  No.  XI.  In  both  of 
these  tables  the  agreement  between  the  sample  delivered  by  the  mill  and 
the  sample  obtained  from  the  main  portion  is  very  satisfactory,  especially 
when  we  consider  the  variations  inherent  in  the  processes  of  analysis  for 
high  ash  coals. 


TESTING  OF  SAMPLING  METHODS 


43 


TABLE  XI 

ACCURACY  OF  SAMPLE  GRINDER 

By  Comparison  of  Ash  Values.    Dry  Basis 

DUPLICATE  SAMPLE  OBTAINED  BY  SECOND  PASSAGE  OF  MAIN  PORTION  THROUGH  MILL 


Laboratory 
Number 

Coal 
(Screenings) 

A 

First  aliquot 
of  10  per 
cent  as 
delivered 

B 
Second  aliquot 
of  main 
portion 

8668 

Moultrie    County 

19.61 

19.60 

8934 

«                « 

20.32 

20.38 

8961 

«                « 

20.94 

21.13 

8973 

«                « 

19.21 

19.82 

9011 

«                « 

19.21 

19.17 

9013 

u                       « 

19.62 

19.41 

9025 

Montgomery  " 

13.69 

13-44 

9H3 

Moultrie 

19.64 

19.67 

9U7 

«               « 

19-83 

20.03 

9162 

11                                   U 

20.14 

20.26 

9160 

Montgomery  " 

14.17 

13-89 

9180 

Moultrie 

19.32 

18.94 

9185 

Montgomery  " 

13-30 

13.48 

91-95 

Moultrie 

.      19.72 

19.90 

91.97 

«                      «« 

18.61 

19.18 

9240 

Montgomery  " 

13.20 

12.95 

9242 

Moultrie 

19.82 

19.89 

9244 

«               it 

18.93 

18.96 

9268 

Montgomery  " 

13.48 

13-43 

MOISTURE 

Moisture  Conditions  and  Nomenclature: — The  topic  of  moisture 
control  has  already  been  discussed,  emphasis  having  been  laid  upon  the 
fact  that  at  any  stage  of  the  processes  the  exact  ratio  of  the  moisture 
present  to  the  moisture  of  the  original  mass  must  be  definitely,  known. 
This  implies  that  moisture  changes  do  occur.  Indeed  three  moisture 
conditions  exist  and,  since  under  each  condition  all  of  the  accompanying 
factors  are  modified  to  meet  the  specific  change  in  moisture,  a  special  des- 
ignation is  applied  to  the  coal  for  each  one  of  these  conditions. 

Coal  with  all  of  the  normal  moisture  present  is  designated  as  "wet" 
coal  or  coal  '  *  as  received. ' '  It  relates  to  the  moisture  at  the  time  of  tak- 
ing the  sample.  All  of  the  detail  of  the  processes  for  collecting  and  re- 


44  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

ducing  the  gross  sample  up  to  and  including  the  item  of  sealing  and 
shipping  the  5-pound  sample  involve  the  preservation  of  this  initial 
moisture  without  loss. 

The  second  moisture  status  is  that  wherein  the  "wet"  or  "as- 
received"  coal  has  been  dried  to  a  point  of  substantial  equilibrium  with 
the  moisture  of  the  air,  so  that  in  an  atmosphere  of  average  humidity  it 
would  take  on  or  lose  additional  moisture  very  slowly  or  not  at  all.  In 
this  condition  the  coal  sample  is  said  to  be  "air  dry."  This  is  the  con- 
dition to  which  the  chemist  must  bring  the  sample  in  order  that  the 
processes  of  finer  grinding  and  weighing  may  be  carried  on  without 
change  in  the  moisture  factor.  Obviously  the  amount  of  moisture  lost 
in  passing  from  the  "wet"  or  "as-received"  condition  to  the  "air-dry" 
condition  must  be  carefully  measured.  The  factor  thus  determined  is 
designated  as  the  ' '  loss  on  air  drying. ' '  By  use  of  it  all  of  the  values  ob- 
tained from  analysis  of  the  coal  in  the  * '  air-dry ' '  state  may  be  calculated 
to  the  "wet"  or  "as-received"  condition. 

The  third  condition  recognized  is  that  of  "dry"  coal.  This  is  some- 
times designated  as  the  "oven-dry"  or  "moisture-free"  state.  All  of 
the  values  found  for  the  coal  in  the  "air-dry"  condition  may  be  trans- 
ferred by  calculation  and  made  to  apply  to  the  coal  as  ' i  oven-dry. ' '  The 
necessary  factor  in  this  case  is  the  loss  of  moisture  obtained  from  drying 
the  "air-dry"  sample  at  or  slightly  above  steam  temperature,  as  220°F. 
for  one  hour.  It  is  not  intended  here  to  give  directions  for  carrying  out 
these  processes.  The  terms  employed,  however,  are  of  so  frequent  oc- 
currence, and  in  many  cases  enter  so  vitally  into  a  correct  understand- 
ing of  the  methods  upon  which  certain  values  are  based  in  the  making 
of  estimates  and  arriving  at  fuel  settlements  that  at  least  a  brief  refer- 
ence seems  desirable. 

Carelessness  in  the  use  of  these  terms  leads  to  much  confusion.  The 
chemist  and  the  engineer  are  not  always  in  agreement  as  to  their  mean- 
ing. The  results  as  obtained  by  chemical  analysis  upon  the  air  dry  sam- 
ple are  of  little  use  to  the  engineer,  whose  basis  of  reference  is  to  the  ' '  as- 
received"  or  to  the  "dry"  basis.  For  the  purpose  of  the  engineer  it  is 
necessary,  therefore,  to  calculate  the  results  which  are  obtained  on  the 
air  dry  sample  back  to  the  "wet"  coal  and  also  to  the  "dry"  basis. 

Calculations: — To  calculate  the  percentage  values  obtained  on  "air- 
dry  ' 7  coal  to  the  ' '  dry-coal ' '  basis,  divide  each  constituent  by  ( 1 — iv )  in 
which  w  is  the  moisture  present  in  the  "air-dry"  sample.  The  moisture 
factor  for  the  "dry"  coal  is  omitted  of  course,  and  the  sum  of  the  result- 
ing constituents  should  total  100  per  cent. 

To  calculate  from  the  "air-dry"  values  to  the  "wet,"  or  "as-re- 
ceived," condition  multiply  each  percentage  for  the  "air-dry"  state  by 
(1 — £)in  which  I  is  the  loss  on  air  drying.  The  moisture  factor  thus 


INTERPRETATION  OF  RESULTS 


45 


derived  plus  the  loss  on  air  drying  equals  the  total  moisture  in  the  ' '  wet ' ' 
coal.  This  and  the  other  factors  calculated  as  described  should  equal 
100  per  cent. 

INTERPRETATION  AND  USE  OP  ANALYTICAL  RESULTS 

General  Plan: — The  general  purpose  involved  in  making  a  chemical 
analysis  of  coal  is  to  furnish  a  basis  for  estimating  values.  In  its  sim- 
plest form  it  consists  in  separating  the  inorganic  or  non  combustible 
from  the  organic  or  heat-producing  material.  The  following  outline 
may  serve  as  an  illustration : 


Coal 


Inorganic 

or 
Non-combustible 


Organic 

or 
Combustible 


Moisture 


Plant  Ash 

Clayey  Matter 

Calcium  Sulphate 

Calcium  Carbonate 

Salt 

Iron  Pyrites 


f  Complex 
•j  Hydrocarbon 
I  Compounds 


Water 


Ash 


I  Combustible 


It  will  be  seen  from  the  diagram  that  the  constituents  of  funda- 
mental importance  are  in  reality  only  three  in  number :  Water,  ash,  and 
combustible  matter.  The  meaning  and  use  of  these  values  especially  in 
some  sort  of  their  modified  or  corrected  forms  may  be  made  of  great 
service  in  connection  with  the  purchase  and  sale  of  coal  on  specification. 

The  Interpretation  of  Moisture  Values: — The  significance  of  the 
factor  for  moisture  is  important.  In  coals  with  high  moisture  in  the 
vein,  a  large  shrinkage  in  weight  occurs  in  the  process  of  shipment.  In 
the  majority  of  cases,  settlement  is  made  upon  the  basis  of  the  mine 
weights.  This  loss  of  moisture,  therefore,  falls  ultimately  upon  the 
consumer. 

There  is  a  certain  agreement  also  between  combined  oxygen  or  the 
water  of  constitution  and  the  content  of  free  moisture  in  the  vein  sam- 
ple ;  the  higher  the  moisture,  the  more  combined  oxygen  and  the  smaller 
the  percentage  of  combustible  in  the  volatile  matter.  For  this  reason 
there  are  more  heat  units  per  pound  of  combustible  (ash  and  moisture 
free)  in  Pocahontas  coal,  with  2  per  cent  of  vein  moisture,  than  per 
pound  of  combustible  (ash  and  moisture  free)  in  Illinois  coal,  with  12 


46  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

per  cent  of  moisture  in  the  vein  sample.  The  vein  moisture,  therefore, 
becomes  to  a  very  considerable  extent  an  index  of  the  type  or  composi- 
tion of  the  organic  part  of  the  coal.  These  variations  in  property  will 
be  discussed  somewhat  further  under  the  topic  of  Unit  Coal. 

Ash. — Ash  is  the  inorganic  constituent  of  the  coal  aside  from  water. 
As  commonly  defined,  it  is  the  residue  left  after  burning  and  is  made 
up  of  complex  substances  such  as  sand,  shale  or  kaolin,  gypsum,  calcium 
carbonate,  iron  pyrites,  etc.  But,  from  the  list  it  is  evident  that  there  is 
much  opportunity  for  loss  of  constituents  such  as  combined  water  and 
C02  in  the  process  of  burning,  which,  if  not  corrected  for,  come  to  be 
reckoned  as  part  of  the  combustible  matter.  There  have  come  into  use, 
therefore,  in  connection  with  the  ash  determination  two  terms  expressive 
of  this  material;  namely,  "ash  as  weighed"  or  simply  "ash,"  and  "cor- 
rected ash." 

The  use  of  a  corrected  ash  factor  is  primarily  of  interest  in  the  ac- 
curate determination  of  the  amount  of  active  or  organic  matter  pres- 
ent. Thus,  unless  the  line  of  demarcation  between  the  organic  and  in- 
organic substance  is  properly  and  precisely  drawn,  we  do  not  have  a  cor- 
rect unit  for  the  true  combustible  material.  This  point  will  be  better  un- 
derstood from  the  discussion  of  the  next  topic,  Unit  Coal. 

Unit  Coal : — In  fuel  literature  three  terms  have  come  into  use : 

1.  Combustible. 

2.  Ash  and  Water  Free  Substance. 

3.  Pure  Coal. 

These  terms  are  synonymous  and  are  intended  to  represent  the  active  or 
actual  coal  substance.  The  heat  value,  for  example,  when  referred  to 
the  combustible  matter,  is  found  by  dividing  the  heat  value  as  obtained 
on  the  west  coal  by  1 — (sum  of  moisture  and  ash  as  weighed).  From 
the  discussion  in  the  previous  paragraph  it  is  evident  that  there  will  be 
a  very  considerable  error  unless  we  make  use  of  a  corrected  ash,  hence 
there  has  been  suggested*  another  term,  that  of  Unit  Coal,  which  is  in- 
tended to  stand  for  the  pure  or  actual  coal  substance  as  derived  from 
taking  into  consideration  the  corrected  ash.  In  other  words  the  attempt 
is  made  to  differentiate  between  the  non-coal  substance  and  the  coal  it- 
self. The  latter  is  a  fairly  constant  material  in  its  heat  producing  prop- 
erty and  general  make-up  of  its  chemical  compounds.  The  non-coal  sub- 
stance on  the  contrary  is  made  up  of  a  number  of  ingredients,  more  or 
less  adventitious,  and  varying  both  in  actual  amount  present  and  also 
in  composition  as  they  pass  through  the  processes  of  analytical  determi- 
nation. For  example  the  iron  pyrites  which  is  a  large  factor  in  the  non- 
coal  material  is  weighed  out  with  the  coal  in  the  form  of  FeS2.  After 

"Illinois  Eng.  Exp.  Sta.  Bulletin  No.  37. 


UNIT  COAL  47 

burning  to  ash  it  becomes  Fe,03  and  the  application  of  a  correction  fac- 
tor to  the  ash  as  weighed  is  necessary  if  we  wish  to  revert  to  the  original 
condition  of  the  ash.  Similarly,  the  shale  or  clayey  constituents  have  in 
chemical  combination,  a  certain  amount  of  water  which  is  not  driven  off 
by  drying  at  steam  temperature,  but  is  delivered  at  a  red  heat  in  the 
process  of  ashing.  Here  again,  if  we  wish  to  obtain  a  factor  for  the  true 
ash  or  non-coal  substance  we  must  apply  another  correction  to  account 
for  this  loss  of  combined  water.  An  expression,  therefore,  for  the  non- 
coal  substance  has  been  adopted  as  follows: 

Non-coal  -  =  Moisture  +  Ash-as-weighed  +  *>/8  S  +  .08  (Ash-as- 
w.-ijrhed  --  10/8  S). 

The  factors  in  this  expression  are  derived  as  follows :  In  the  ash  as 
weighed  the  FeS2  of  the  original  coal  has  burned  to  Fe._,03.  In  this  com- 
bination the  atomic  ratio  of  the  oxygen  to  the  total  sulphur  which  it  re- 
places in  the  original  FeS2  (that 'is,  2  (FeS2) )  is  48  : 128  or  3  :  8,  That  is 
to  say — oxygen  has  combined  with  the  iron  to  the  extent  of  3/8  of  the 
original  sulphur.  Hence  the  ash  as  weighed  may  be  corrected  or  brought 
to  its  original  form  so  far  as  the  FeS2  is  concerned  by  adding  5/8  of  the 
weight  of  the  sulphur  present  in  the  coal. 

Again  the  ratio  of  iron  to  sulphur  in  iron  pyrites  (FeS2)  is  56  :  64; 
that  is,  the  amount  of  iron  present  is  7/8  of  the  weight  of  the  sulphur. 
The  combined  iron  and  oxygen,  therefore,  weighed  as  Fe203  are  equiva- 
lent to  7/8  -f-  3/8  or  10/8  of  the  sulphur  present.  Hence  the  expression 
(Ash-as-weighed  -  -  10/8  S)  represents  the  ash  with  the  pyritic  iron  or 
the  resulting  oxide  Fe20:>  removed.  Therefore,  since  the  original  FeS2 
from  which  it  comes  has  no  combined  water,  it  is  subtracted  before  ap- 
plying the  correction  constant  of  0.08.  This  8  per  cent  is  a  constant  and 
represents  the  water  of  hydration  for  the  clayey  constituents  which  we 
wisli  to  restore  to  the  ash  as  in  its  original  form. 

The  above  formula  for  "non-coal"  becomes  therefore  the  expres- 
sion for  the  true  coal  or  1 1  Unit  Coal ' '  in  percentage  values  as  follows : 

Unit  Coal  =  100  -  (Water  -f  Ash-as-weighed  +  5/8  S  -f 
.08  (Ash-as.- weighed  — 10/8  S). 

By  clearing  of  fractions  and  bringing  to  its  simplest  form,  this  ex- 
pression becomes : 

Unit  Coal  ==  100  --  (W  +  1.08  A  -f  21/40  S)  in  which  W  is  the 
percentage  of  water,  A  is  the  percentage  of  ash-as-weighed,  and  S  is  the 
sulphur  content.  In  this  expression  the  factor  21/40  S  can  not  be 
further  simplified  by  making  it  1/2  S,  for  the  reason  that  our  correction 
for  sulphur  is  already  too  small  by  that  part  of  the  organic  sulphur  not 
covered  by  the  addition  to  the  ash  value  of  3/8  of  the  total  sulphur  in- 
dicated in  the  original  formula.  On  the  contrary,  we  shall  be  approach- 
ing nearer  the  truth  by  increasing  slightly  the  sulphur  correction,  which 


48  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL.  ETC. 

may  be  done  with  convenience  in  calculating,  by  making  this  factor 
read  22/40  S  or  1/2  S  +  1/20  S. 

Sulphur: — This  constituent  of  the  ash  is  made  a  matter  of  separate 
determination.  The  question  might  be  raised  as  to  whether  the  sulphur 
should  not  be  grouped  with  the  true  coal  substance  since  it  contributes 
somewhat  to  the  heat  values  in  the  burning  process.  But  it  is  distinctly 
a  mineral  substance,  varies  widely  in  amount  and  affects  the  properties 
of  the  coal  far  more  specifically  through  the  ash  than  in  its  contribution 
to  the  heat  volume,  which  is  relatively  small  in  amount.  Moreover,  by 
segregating  it  from  the  heat  producing  constituents  and  taking  away 
the  heat  also  which  may  be  credited  to  it  a  far  more  consistent  value 
remains  as  the  true  heat  to  be  credited  to  the  Unit  Coal  substance.  This 
procedure  will  be  found  to  have  very  great  practical  value  as  well  as  be- 
ing of  great  advantage  in  the  comparative  study  of  coals  for  classifica- 
tion and  similar  purposes.  Since  the  sulphur  of  coal  occurs  chiefly  as 
iron  pyrites,  FeS2,  it  is  generally  believed  that  a  high  sulphur  factor 
represents  a  high  iron  factor  and,  consequently,  a  tendency  for  the  coal 
to  clinker  in  burning.  This  does  not  necessarily  always  follow,  but  it 
is  true  in  the  main.  The  average  content  of  sulphur  in  Illinois  coals  is 
from  3  to.  4  per  cent,  with  an  occasional  output  as  high  as  six  or  even 
seven  per  cent.  In  the  southern  and  southeastern  field,  however,  as  in 
Franklin,  Williamson,  Saline  and  Jackson  Counties,  the  sulphur  con- 
tent will  average  from  1  to  2  per  cent. 

Volatile  Matter  and  Fixed  Carbon: — The  organic  matter  of  coal 
when  heated  above  500  or  600  degrees  decomposes  giving  off  combusti- 
ble gases  and,  if  the  temperature  is  continued  to  a  bright  red  heat,  there 
remains,  in  addition  to  the  ash,  the  fixed  carbon  or  coking  constituent 
of  the  coal.  The  volatile  matter  is  of  significance  largely  by  reason  of 
the  fact  that  this  part  of  the  combustible  substance  has  a  tendency  to 
escape  into  the  flue  spaces  before  complete  combustion  has  been  effected. 
With  mechanical  stokers  and  modern  equipment,  this  would  not  occur 
and,  consequently,  the  matter  of  high  or  low  volatile  matter  is  of  less  sig- 
nificance than  formerly.  In  domestic  appliances,  however,  this  is  not 
the  case,  and  larger  losses  occur  in  the  process  of  combustion!  For  such 
uses,  therefore,  higher  efficiency  will  be  obtained  from  coals  with  less 
volatile  matter  and  a  higher  percentage  of  fixed  carbon. 

Fixed  Carbon: — The  fixed  carbon  represents  the  amount  of  com- 
bustible matter  which  remains  behind  for  complete  combustion  in  the 
fire  box.  Its  value,  therefore,  depends  upon  the  form  of  appliance  in 
which  the  coal  is  burned.  The  fixed  carbon  plus  the  ash  represents  ap- 
proximately the  coke  content  that  might  be  expected  from  the  original 
coal. 


CALORIMETRY  49 

CALORIMETRIC  MEASUREMENTS 

Definitions: — Heat  values  are  expressed  in  two  ways, — as  Calories 
and  as  British  thermal  units.  Only  the  large  Calorie  is  made  use  of  in 
fuel  reference  and  it  represents  the  amount  of  heat  necessary  to  raise 
1  kilo  of  water  through  1°C.  The  full  expression  is,  therefore,  Calories 
per  kilo  or  kilo-Calories. 

The  British  thermal  unit  represents  the  amount  of  heat  necessary 
to  raise  1  pound  of  water  through  1°F.  The  full  expression,  therefore, 
would  be  B.t.u.  per  pound. 

Since  the  Centigrade  degree  is  9/5  or  1.8  times  as  great  as  the  Fah- 
renheit degree,  and  the  kilo  is  2.2046  times  the  pound,  it  follows  that  one 
Calorie  would  be  the  equivalent  in  Fahrenheit  degrees  of  1.8  X  2.2046 
or  3.968  B.t.u.  However,  the  comparison  between  units  as  thus  devel- 
oped is  not  a  comparison  between  values  as  made  use  of  in  the  case  of 
fuels  for  the  reason  that  the  arbitrary  amount  of  coal  to  which  reference 
is  made  in  both  cases  is  an  amount  of  coal  equal  to  the  unit  of  water  de- 
veloped, that  is  a  kilo  of  coal  to  a  kilo  of  water,  a  pound  of  coal  to  the 
pound  of  water.  For  this  reason,  therefore,  the  rise  in  temperature 
in  each  case  is  the  same.  That  is,  a  pound  of  coal  will  raise  the  temper- 
ature of  a  pound  of  water  through  as  many  degrees  as  a  kilo  of  coal  will 
raise  a  kilo  of  water,  or  a  ton  of  coal  a  ton  of  water,  etc.  The  difference 
in  heat  values  as  expressed  by  these  two  methods,  therefore,  is  simply 
the  difference  in  the  thermometric  readings.  A  reading  taken  by  the 
Fahrenheit  scale  will  be  9/5  or  1.8  times  as  great  as  the  reading  taken 
by  the  Centrigrade  scale.  Therefore,  to  change  fuel  values  expressed 
in  Calories  per  kilto  to  B.t.u.  per  pound,  multiply  by  1.8. 

Heat  Values  by  Calculation: — Heat  values  may  be  determined  from 
the  ultimate  anaylsis  by  Dulong's  formula,  which  assumes  that  the  heat 
comes  from  the  combustion  of  carbon,  hydrogen,  and  sulphur.  The  us- 
ual values  for  these  constituents  are 

Carbon  =    8,080  Cal.  or  14,544  B.  t.  u. 

Hydrogen  =  34,500  Cal.  or  62,100  B.  t.  u. 

Sulphur  =       2,500  Cal.  or  4,500  B.  t.  u. 

Expressed  in  the  latter  set  of  values,  therefore,  Dulong's  formula  be- 
comes 

14,544  C  +  62,100  (H  -     ?)   +  4,500  S  =  B.t.u. 

8 

In  this  formula  the  expression  (H—        )  represents  what  is  termed 

8 

The  available  hydrogen ;  that  is,  the  amount  left  after  subtracting  the 
equivalent  hydrogen  needed  to  unite  with  the  oxygen  present  to  form 
water,  2:16  or  1/8  0. 


50  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

Presumably  such  calculated  values  would  be  in  close  agreement 
with  indicated  values  by  means  of  a  carefully  operated  instrument.  This 
is  true  for  certain  regions,  but  not  for  others.  The  divergence  is  more 
pronounced  in  coals  of  this  region  than  in  the  coals  of  the  Eastern  United 
States.  "In  view  of  the  possible  presence  of  calcium  carbonate  and  the 
consequent  error  in  the  ash  determination  for  many  Illinois  coals,  it  is 
evident  that  a  direct  variable  in  such  cases  enters  into  the  value  for  oxy- 
gen and  consequently  for  the  available  hydrogen,  which  would  thereby 
result  in  a  discrepancy  as  between  the  indicated  and  the  calculated  ca- 
lorific values.  Moreover,  a  high  percentage  of  oxygen  in  combination  evi- 
dently may  be  responsible  for  variations  of  quite  a  different  character, 
as,  for  example,  a  different  distribution  of  such  oxygen  in  a  manner  not 

altogether  correctly  covered  by  the  expression  —  ,  or  in  the  ultimate 

8 

form  of  water.  There  seems  to  be,  therefore,  numerous  reasons  why  'a 
calculated  calorific  value  by  use  of  Dulong's  formula  is  of  little  value 
for  coals  of  this  type. '  '* 

Derivation  of  Heat  Values  for  Unit  Coal: — It  is  obvious  that  if  the 
heat  value  of  the  unit  coal  is  constant  within  narrow  limits  for  a  given 
mine  or  region  we  may  if  such  unit  values  are  known,  reverse  the  cal- 
culation, making  use  of  any  assigned  values  for  moisture,  ash  and  sul- 
phur, and  so  determine  by  calculation  the  heat  value  of  commercial  pro- 
duct for  that  particular  mine  or  region  for  which-  the  unit  coal  value  is 
a  constant.  We  shall  need  to  discuss  in  the  first  place,  therefore,  the 
method  of  calculating  unit  coal  values. 

From  our  previous  discussion  of  the  formula  which  has  been  de- 
veloped to  represent  the  percentage  of  unit  coal,  it  is  readily  seen  that 
the  expression  for  deriving  the  heat  value  for  that  substance  would  be 
as  follows:  Using  "W"  for  water,  "A"  for  Ash,  and  "S"  for  sulphur. 
For  coals  with  values  given  on  the  "as-received"  or  "wet"  basis: 

Indicated   (Wet)   B.t.u.— 5,000  S. 
B.t.u.  of  Unit  Coal 


1.00  —  (W+1.08A+ 22/408) 
For  coals  with  values  given  on  the  ' '  dry ' '  or  moisture  free  basis : 

Indicated  (dry)  B.t.u.  —  5000  S 


B.t.u.  of  Unit  Coal  = 


1.00—  (1.08A  +  22/40  S) 


*Parr,  S.  W.,  .111.,  S.  G.  S.  Yearbook,  1909,  p.  236. 

Also,  Porter  and  Ovitz,  Bureau  of  Mines,  Bulletin  No.  i,  p.  28-29. 


UNIT  FUEL- VALUES  51 

The  expression  5000  S  has  been  used  as  indicating  the  heat  due  to 
the  combustion  of  sulphur,  for  the  reason  that  the  value  4500  S  as  used 
in  Dulong's  formula  represents  the  heat  of  combustion  for  pure  sul- 
phur, while  the  heat  of  combustion  of  sulphur  in  the  form  of  pyrites, 
FeS2,  combines  also  the  heat  of  formation  of  iron  oxide,  Fe203.  It  is 
the  resultant  value,  therefore,  of  the  several  reactions  involved  that  is 
desired. 

According  to  the  direct  tests  by  Somermeier,*  in  the  combustion  of 
coal  with  known  wights  of  iron  pyrites,  the  indicated  heat  per  gram  of 
sulphur  so  combined  is  4957  calories.  In  calculating  heat  values,  the 
correction  introduced  for  the  combinations  resulting  from  calorimeter 
reactions  as  compared  with  open-air  combustion  is  2042  calories  per 
gram  of  pyritic  sulphur;  hence  4957  —  2042  or  2915  calories  (5247 
B.t.u. )  represents  the  heat  due  to  burning  one  gram  of  sulphur  in  pyritic 
form  instead  of  2250  calories  (4050  B.t.u.),  the  amount  which  would  be 
credited  to  sulphur  in  the  free  condition.  A  strict  application  of  these 
values,  therefore,  would  call  for  a  correction  of  5247  S,  as  representing 
the  heat  to  be  subtracted  for  the  sulphur.  This,  however,  would  imply 
that  all  of  the  sulphur  is  in  the  pyritic  form.  Since  a  certain  portion  of 
the  sulphur  is  always  present  in  organic  or  other  form  of  less  heat-pro- 
ducing capacity,  it  is  deemed  more  nearly  correct  to  use  an  even  factor 
of  5000  as  representing  the  heat  to  be  credited  to  unit  amounts  of  the 
total  sulphur  present. 

By  computing  the  heat  values  as  derived  by  this  formula  for  solid 
fuels  throughout  the  United  States,  as  published  by  the  United  States 
Geological  Survey,  the  Ohio  State  Survey,  and  the  Illinois  Geological 
Survey,  we  have  in  tabular  form,  giving  the  extremes  for  each  general 
fuel  type,  the  following : 

TABLE  XHI 

CLASSIFICATION    OF    FUEL    TYPES    BY    HEAT    VALUES    FOR    UNIT    COAL%  OR   ACTUAL 

ORGANIC  SUBSTANCE 

B.t.u. 

Cellulose  and  wood 6,500  to     7,800 

Peat  :. 7,800  to  11,500 

Lignite,   brown   11,500  to  13,000 

Lignite,  black,  or  sub-bituminous  coal 13,000  to  14,000 

Bituminous  coal  (mid-continental  field) 14,000  to  15,000 

Bituminous  coal   (eastern  field) 15,000  to  16,000 

Semi-anthracite   and   semi-bituminous 15,500  to  16,000 

Anthracite   15,000  to  15,500 

'"Jour.  Am.  Chem.  Soc.    Vol.  26,  p.  566. 


52  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

This  study  has  been  carried  still  further  by  the  Illinois  State  Geological 
Survey,  and  the  extremes  have  been  derived  for  the  various  seams  as 
worked  throughout  the  coal  area  of  the  State. 

It  is  to  be  recalled  that  the  geologists  recognized  16  coal  seams  for 
Illinois,  counting  from  the  bottom  of  the  coal  measures  upward.  Only 
seven  of  these  seams  are  of  workable  thickness.  The  numbering  follows 
the  geological  order,  and.  not  that  used  in  some  localities,  as  at  LaSalle, 
Bloomington,  etc.,  where  the  number  of  the  seam  is  that  which  resulted 
from  the  order  of  their  development  from  the  surface  downward. 

In  table  No.  XIV  a  few  illustrative  examples  are  given  of  unit  coal 
values.  Complete  tables  covering  all  of  the  producing  counties  of  the 
state  have  recently  been  published*  from  which  these  figures  have  been 
taken : 

TABLE  XIV 
AVERAGE  HEAT  VALUE  FOR  UNIT   COAL  IN   BRITISH   THERMAL  UNITS    PER   POUND 


No. 

County 

Coal  bed 

Number  of  sam- 
ples averaged 

Average  —  B.  t.  u. 
"unit  coal" 

i 

Sangamon 

c 

T  C 

14424 

2 

Sangamon 

6 

C 

14^40 

-2 

Macoupin 

6 

6 

I4^IO 

A 

Madison 

6 

18 

I4^O 

z 

Vermilion 

6 

IQ 

14597 

6 

Vermilion     ..     ..'    . 

7 

Q 

14730 

7 

Williamson  

6 

c 

1  47  So 

Calculation  of  Commercial  Values: — The  use  which  can  be  made  of 
these  "unit"  values  such  as  are  shown  in  this  table  may  be  readily  un- 
derstood when  it  is  remembered  that  each  number  represents  material 
which  is  100  per  cent  pure  and  that  for  each  per  cent  of  inert  matter 
present,  such  as  water  and  ash,  there  is  a  corresponding  decrease  in  the 
number  of  heat  units  present.  That  is  to  say,  if  a  coal  has  20  per  cent 
water  and  ash,  then  80  per  cent  of  the  "unit"  value  will  represent  the 
heat  units  present  per  pound  of  coal  as  delivered.  Indeed,  it  is  possible 
by  taking  account  of  certain  refinements  already  referred  to,  such  as 
correction,  factors  for  sulphur  and  hydration  of  the  shaly  constituents, 
to  make  a  calculation  which  will  be  of  quite  sufficient  accuracy  for  basing 
bids  and  entering  into  contracts  involving  a  guarantee  as  to  heat  values. 


"111.  State  Geol.  Survey.    Bulletin  No.  29.    "Purchase  and  Sale  of  Illinois  Coals 
on  Specification"  by  S.  W.  Parr,  1914. 


COMMERCIAL  ESTIMATES  53 

The  method  of  calculation  is  exceedingly  simple  and  is  based  on  the  fol- 
lowing expression : 

Let  A  ==  weight  of  ash  per  pound  of  coal. 

Let  S  ==  weight  of  sulphur  per  pound  of  coal. 

Then— 

"Dry"  B.t.u.  ==  "Unit"  B.t.u.  X  [1.00  --  (1.08A  +  0.55S)]  -f 
5000S.  . 

To  illustrate,  take  the  "unit"  value  for  coal  from  Vermilion  County, 
Sample  No.  6  in  Table  XIV.  Suppose  we  wish  to  know  what  heat  value 
can  be  guaranteed  on  deliveries  from  a  mine  of  this  group  on  the  basis 
that  we  can  furnish  material  averaging  as  the  "dry  coal,"  12  per  cent 
ash,  and  3  per  cent  sulphur,  we  will  have  our  total  non-combustible 
material  corrected  by  the  above  formula  as  follows: 

1.08A 12.96 

0.55S .  1.65 


Total 14.61 

100%  -  -  14.61%  =  85.39% 
14730  X  85.39%  =  12578 

In  this  calculation  the  sulphur  has  been  neglected.  It  has  a  small 
heat  value  equal  to  5000  times  the  weight  of  sulphur  present  or  50  times 
the  percentage  number,  thus: 

50  X  3  =  150  units  to  be  added  to  the  above  value,  or 
12578 
150 


12728  B.t.u. 

Deliveries  from  this  mine,  therefore,  having  ash,  and  sulphur  as 
indicated  above  can  be  depended  upon  as  carrying  12728  heat  units  per 
pound  of  * '  dry ' '  coal,  and  this  factor  should  be  accurate  within  100  units 
in  12000  or  less  than  a  variation  of  1  per  cent  from  values  as  they  would 
be  determined  by  direct  reading  from  an  instrument.  Any  other  set 
of  values  for  ash  and  sulphur  would  similarly  admit  of  ready  calculation 
and  should  be  used  as  a  basis  for  calculations  involving  guarantees  of 
deliveries  on  a  heat-unit  basis.  If  the  heat  units  on  the  "wet"  coal 
basis  are  desired  assuming,  for  example,  a  moisture  factor  of  15  per  cent, 
the  above  value  as  derived  for  "dry"  coal  should  be  multiplied  by  .85, 
that  is,  12728  B.t.u.  X  .85  ==  10818  B.t.u.  per  pound  of  the  "wet"  coal, 
assuming  a  moisture  factor  of  15  per  cent  as  indicated. 

DIRECT  DETERMINATION  OF  HEAT  VALUES 

The  Berthier  Test: The  Berthier  test  is  based  on  the  property  of 

carbon  to  reduce  the  oxide  of  lead  at  a  red  heat.    The  higher  the  percen- 


54 


THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


tage  of  combustible  present,  the  larger  the  button.  One  gram  of  coal  is 
mixed  with  2  cz.  or  60  grams  of  litharge  and  heated  to  redness  in  a  cruci- 
ble. The  weight  of  the  button  thus  obtained  is  multiplied  by  the  421. 
The  product  represents  theoretically  the  reducing  power  of  the  carbon 
in  terms  of  British  thermal  units.  It  should  be  increased  by  about  the 
value  of  the  available  hydrogen  present.  In  Illinois  coals  this  does  not 
vary  widely  from  3.5  per  cent,  making  the  addition  of  a  constant  neces- 
sary of  about  2000  B.t.u.  The  results  thus  obtained  may  vary  from  the 
truth  by  300  to  800  units,  or  from  3  to  8  per  cent.  The  method  has  his- 
torical rather  than  practical  interest. 

The  Lewis  Thompson  calorimeter  is  a  bell  shaped  receptacle  for  sub- 
merging water  and  containing  within  the  bell  a  cartridge  having  a  mix- 
ture of  coal,  2  grams;  with  22  grams  of  a  mixture  of  potassium  nitrate 
3  parts,  and  potassium  chlorate,  1  part.*  Occording  to  Schorer-Kest- 
ner**  this  apparatus  normally  gives  results  that  are  in  error  by  about  15 
per  cent.  This  apparatus  also  dates  back  to  a  time  when  a  mere  approx- 


Fig.   ii.     Filling  an  Oxygen  Bomb  from  a  High-pressure  Cylinder  Supply 
(Courtesy  of  the  Standard  Calorimeter  Co.,  East  Moline,  111.) 

imation  to  the  correct  values  was  all  that  seemed  to  be  demanded  by  fuel 
users.  At  the  present  time  a  degree  of  exactness  is  required  which  was 
impossible  with  either  of  the  methods  just  described. 

There  are  two  types  of  calorimeters  using  oxygen  as  a  medium  for 
carrying  on  the  combustion, — those  in  which  the  oxygen  is  maintained 

*For  details  of  the  Apparatus  see  Fuel,  Water  and  Gas  Analysis.     By  Kershaw. 
**Jour.  Soc.  Chem.  Ind.  Vol.  /,  p.  869. 


OXYGEN  BOMB  CALORIMETERS 


55 


at  atmospheric  pressure  and  those  using  oxygen  under  approximately 
25  atmospheres. 

Of  the  first  type,  the  best  known  perhaps  are  Fischer's,  Carpen- 
ter's, W.  Thompson's,  etc.,  which  conduct  a  current  of  oxygen  into  a 
chamber  containing  the  fuel.  The  chief  disadvantage  results  from  im- 
perfect combustion,  especially  with  high  ash  coals  due  to  fusion  of  the 
ash  with  consequent  enclosure  and  protection  of  the  carbonaceous  mat- 
ter from  further  oxidation. 

I 


Fig.  12.     Oxygen   Calorimeter   Dismantled 

Oxygen  Bomb  Calorimeters: — Calorimeters  using  oxygen  at  ap- 
proximately 25  atmospheres  pressure  are  designated  as  of  the  Berthelot 
or  Mahler  type  from  the  names  of  the  investigators  who  were  pioneers 
in  their  development  and  use.  A  typical  bomb  of  this  type  is  shown 
in  Fig.  11  connected  with  the  high  pressure  oxygen  supply  for  charg- 
ing. A  carefully  weighed  amount  of  coal  is  held  in  a  capsule  within  the 
bomb.  The  bomb  after  charging  is  placed  in  the  can  A,  Fig.  12,  and  a 


56  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

known  quantity  of  water  added.  After  placing  in  the  insulated  recep- 
tacle B,  and  putting  in  place  the  cover  C,  an  equalization  of  tempera- 
tures is  brought  about  by  rotation  of  the  stirrer.  After  ignition  and 
equalization  again  of  the  temperature,  the  factors  are  at  hand  for  de- 
riving the  heat  value  of  the  coal  according  to  the  formula : 

rise  X  total  water 
:  Wt.  of  coal 

For  example,  if  one  gram  of  coal  were  taken  and  the  total  water  used, 
including  the  water  equivalent  of  the  apparatus,  were  2400  grams,  then 
for  a  rise  of  say,  4°  Fah.  the  heat  value  would  be  9600  B.t.u.  By  this 
procedure,  therefore,  may  be  found  the  rise  in  temperature  which  a 
given  weight  of  coal  will  impart  to  an  equivalent  weight  of  water,  thus 
satisfying  the  conditions  of  the  definition  of  the  British  thermal  units 
per  pound  of  fuel. 

Radiation  Corrections: — If  the  system  containing  the  bomb  and 
measured  quantity  of  water  is  operated  at  a  temperature  above  or  below 
that  of  the  room  a  gain  or  loss  of  heat  will  result  due  to  radiation.  This 
may  be  corrected  for  in  a  very  accurate  manner  by  taking  the  thermom- 
eter readings  each  minute  for  a  preliminary  period  of  five  minutes  and 
also  for  a  final  period  of  five  minutes.  The  rates  of  radiation  change 
thus  obtained  are  incorporated  into  a  formula  covering  the  period  of 
combustion  and  equalization  of  the  system.  Details  of  procedure  and 
calculations  are  given  under  directions  for  manipulation  (Part  II, 

P.  in). 

Adiabatic  Insulation: — To  avoid  the  necessity  of  accounting  for  ra- 
diation losses  and  eliminating  possible  errors,  as  also  to  simplify  the 
matter  of  readings  and  calculations,  various  methods  of  insulation  in- 
volving adiabatic  conditions  have  been  developed.  To  be  thoroughly  ef- 
fective these  methods  should  involve  complete  control  over  the  temper- 
ature of  the  insulating  part  of  the  apparatus  in  such  a  way  as  to  cause 
the  temperature  to  rise  coordinately  with  that  of  the  combustion  sys^ 
tern.  Such  instruments  are  designated  as  adiabatic  calorimeters.  Their 
greater  convenience  of  operation  and  possibilities  of  extreme  accuracy 
are  apparent. 

Acid  Values: — One  other  condition  exists  in  the  use  of  the  Mahler 
type  of  calorimeter  which  requires  consideration.  Because  of  the  use 
of  pure  oxygen  at  a  high  pressure  and  temperature,  certain  reactions 
take  place  which  do  not  occur  in  the  ordinary  process  of  combustion. 
For  example,  a  small  amount  of  residual  air  present  upon  closing  the 
instrument  has  free  nitrogen  which  under  the  conditions  of  combustion 
is  partially  oxidized  to  N205  or  with  the  moisture  present  in  the  bomb 
it  becomes  HN03.  Similarly  the  nitrogen  of  the  coal  burns  to  a  greater 


THE  PEROXIDE  CALORIMETER  57 

or  less  extent  to  HN03.  The  sulphur  in  the  coal  which  under  ordinary 
conditions  of  combustion  burns  to  S02,  in  the  calorimeter  burns  to  SO3 
or  with  the  moisture  present,  to  H2S04.  These  two  highly  corroding 
acids  make  it  necessary  to  protect  the  interior  surface  of  the  bomb.  This 
is  accomplished  by  use  of  an  enamel,  by  a  spun  lining  of  gold  or  plati- 
num, or  by  constructing  the  bomb  of  an  acid  resisting  alloy  equivalent 
in  that  respect  to  gold  or  platinum.  If  such  a  precaution  is  disregarded, 
as  for  example,  if  the  enamel  type  of  protection  becomes  cracked  and 
scaled  off  or  if  a  lining  of  spun  metal  such  as  nickel  is  employed,  the 
solvent  property  of  the  acids  becomes  active.  There  are  two  sources  of 
error  which  result  from  such  conditions, — one  is  the  heat  of  solution  re- 
sulting from  the  chemical  action.  This  of  course  should  not  be  credited 
to  the  heat  content  of  the  coal.  The  other  is  the  lowering  of  the  amount 
of  free  acid  which  thus  escapes  measurement  and  otherwise  would  be 
corrected  for.  In  high  sulphur  coals  of  the  Illinois  type  the  error  from 
this  source  may  be  of  considerable  moment. 

Details  of  manipulation  and  procedure  for  taking  account  of  the 
various  corrections  to  be  applied  with  the  attending  methods  of  calcula- 
tion are  given  in  connection  with  the  laboratory  directions  in  Part  II. 

Peroxide  Calorimeter: — Another  type  of  calorimeter  is  extensively 
used  in  which  the  coal  is  mixed  with  a  chemical  which  will  supply  the 
oxygen  to  complete  the  combustion  within  a  closed  cartridge.  This 
method  is  more  conveniently  available  perhaps  for  technical  work.  The 
procedure  is  described  under  the  directions  for  calorimetric  measure- 
ments. (Part  II,  p.  98.) 

The  principles  involved  are  as  follows:  Sodium  peroxide,  Na2O2, 
when  mixed  with  coal  in  suitable  proportion  and  ignited,  may  be  made 
to  burn  or  react  through  an  appreciable  period  of  time  but,  instead  of 
the  formation  of  gaseous  products  as  in  the  ordinary  process  of  combus- 
tion, the  C02  and  H20  unite  with  the  chemical  employed  to  form  the 
carbonate  and  hydrate  of  sodium,  which  are  solids.  These  reactions 
shown  in  detail  are  as  follows : 

i  2Nao(X+C=2Na,O+C02 
I  2Na20+ CO2=Na,CO8+Na20 


I  Na202+H2=Na20+H20 
I  Na20+H20=2NaOH 


Of  the  total  heat  developed  in  the  reactions  under -(a),  0.73  repre- 
sents the  heat  combination  between  the  carbon  and  oxygen.  Also,  under 
(b),  the  total  heat  of  the  reactions  is  made  up  of  73  parts,  which  includes 

*The  complete  reactions  involved  are  probably  expressed  by  the  equation — 
Ka0O0-hXa0O4-O-f4H=4NaOH.  (See  "The  Constants  of  the  Parr  Calorime- 
ter."" "jour. "of  the  Am.  Chem.  Soc.,  Vol.  XIX,  p.,  1616). 


58  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

the  heat  formed  by  the  union  of  the  hydrogen  with  the  oxygen,  and  27 
parts,  which  represents  the  secondary  reaction  or  combination  of  the 
water  with  the  chemical.  This  distribution  of  heat  values  is  fortunate 
for  the  reason  that  we  may  make  the  factor  0.73  a  constant  which  repre- 
sents the  part  of  the  total  heat  to  be  taken  as  the  equivalent  of  the  heat 
of  ordinary  combustion.  Other  corrections  must  be  applied  to  the  indi- 
cated rise  in  temperature  as  detailed  in  the  method  of  operation  (Part 
II,  p.  101).  A  brief  discussion  having  reference  to  the  reason  for  apply- 
ing the  corrections  is  here  given. 

First. — The  ignition  is  effected  by  an  electrically  heated  fuse  wire. 
The  amount  of  heat  introduced  by  the  electric  current  and  combustion 
of  the  wire  is  found  to  be  .005°  F. 

Second. — The  combination  of  the  ash  with  the  sodium  peroxide, 
forming  in  the  main  sodium  and  aluminum  silicates,  is  attended  with  a 
slight  increment  of  temperature  which  is  found  by  direct  experiment  to 
amount  to  0.005 °F  for  each  per  cent  of  ash  present  in  the  fuel. 

Third. — The  sulphur  in  ordinary  combustion  burns  to  sulphur  diox- 
ide, S02,  while  in  the  reaction  with  the  chemical  the  ultimate  result  is 
Na2S04.  The  difference  in  the  heat  resulting  from  the  two  reactions 
should  be  subtracted  from  the  indicated  temperature.  The  amount  of 
the  correction  is  determined  by  burning  pure  iron  pyrites,  FeS2,  in  the 
apparatus  and  comparing  the  heat  evolved  with  the  accepted  heat  value 
for  the  combustion  of  an  equivalent  amount  of  sulphur  to  S02*.  The 
difference  is  found  to  be  equivalent  to  0.010 °F  for  each  per  cent  of  sul- 
phur present  in  the  coal. 

Fourth. — For  the  more  perfect  combustion  of  all  types  of  coal 
and  also  for  supplying  the  seemingly  needed  free  or  nascent  oxygen  for 
the  combustion  of  the  hydrogen,  an  accelerator  is  used  in  conjunction 
with  the  sodium  peroxide,  preferably  chlorate  of  potash,  finely  pulver- 
ized and  dry.  .  The  heat  of  decomposition  of  this  material  plus  the  re- 
combination of  the  free  oxygen  with  the  Na2O  resulting  from  the  reac- 
tions with  carbon  amount  to  0.270° F  per  gram  of  KC103  used. 
The  indicated  rise  of  temperature  is,  therefore,  first  corrected  for  the 
several  components  enumerated,  and  the  corrected  rise  is  used  in  the 
formula : 

rXwX0.73 
B.t.u.=        — c- 

in  which  "r"  is  the  corrected  rise  in  temperature,  "w"  is  the  water 
equivalent  of  the  water  and  metal  of  the  apparatus,  2123.3  grams,  and 
"C"  is  the  weight  of  coal  taken,  0.5  gram.  This  will  give  us  the  rise  in 
degrees  Fahrenheit  or  B.t.u.  which  an  equal  weight  of  coal  will  yield 

*Idem,  p.  1620. 


DERIVATION  OF  CONSTANTS  59 

upon  combustion,  provided  the  actual  heat  of  combustion  is  imparted  to 
an  equivalent  of  water. 

Since,  in  the  above  formula  the  factors  for  "w,"  "C,"  and,  the  con- 
stant 0.73  occur  in  all  cases,  their  resulting  value  becomes  a  constant 
equal  to  3100.  Thus, 

3  =3100. 


COMPOSITION  OP  ILLINOIS  COALS 

A  recent  survey  carried  on  by  the  Illinois  State  Geological  Survey 
in  cooperation  with  the  U.  S.  Bureau  of  Mines  covered  all  of  the  coal 
producing  counties  of  Illinois  and  included  something  over  100  mines. 
The  analytical  values  for  the  coals  from  these  mines  have  been  averaged 
for  the  various  counties  and  are  assembled  in  Table  No.  XV.  Where 
mining  operations  are  carried  on  from  different  seams  in  the  same 
county,  the  average  for  the  single  seam  indicated  is  given  separately 
and  not  for  the  county  as  a  whole.  Also,  for  the  reason  that  some  of  the 
seams  vary  widely  in  character  from  north  to  south,  the  letters  "N"  or 
"S,"  are  occasionally  used  to  designate  the  general  region  from  which 
the  samples  are  taken.  Similarly,  since  in  some  rather  restricted  locali- 
ties a  marked  alteration  in  the  seam  occurs  from  East  to  West,  the  let- 
ters "E,"  and  "W,"  are  used  as  in  Perry  County,  the  letter  "E"  signi- 
fies for  seam  No.  6,  East,  and  "W"  west  of  the  DuQuoin  anticline. 

Partial  bibliography  relating  to  coal  calorimetry. 

Lord  and   Somermeier,  Ohio  State  Geological  Survey,   fourth  series,   Bul- 

letin 9,  p.  320. 

Atwater,  Jour.  Am.  Chem.  Soc.,  Vol.  25,  p.  659. 
Parr,  S.  W.,  Jour.  Am.  Chem.  Soc.,  Vol.  29,  p.  1606. 
Parr,  S.  W.,  Jour.  Ind.  &  Eng'g.  Chem.,  Vol.  I,  No.  9,  p.  673. 
investigations  in  the  Use  of  the  Bomb  Calorimeter.     By  J.  A.  Fries.     U.  S. 
Dept  Ag.  Bui.  94.     1907. 

Coal,  Its  Composition,  Analysis,  etc.     By  E.  E.  Somermeier.     1912. 
Technical  Gas  and  Fuel  Analysis.     By  A.  H.  White.     1914. 
Bureau  of  Standards  Scientific  Paper  No.  230.     By  H.  C.  Dickinson. 
The    Function    of    Nitrogen   in   the   Bomb   Calorimeter.      By   S.   A.    Register. 
Jour.  Ind.  and  Eng.  Chem.,  Vol.  6,  p.  812. 

Report  of  the  Committee  £-4  on  Methods  of  Sampling  and  Analysis  of  Coal. 
Proc.  Am.  Soc.  Testing  Mat,  Vol.  X  14,  p.  444;  1914.  Also  Jour.  Ind.  and  Eng. 
Chem.,  Vol.  V,  p.  517;  1913. 


6o 


THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


TALBE  No.  XV. 

AVERAGE  ANALYTICAL  AND   HEAT  VALUES   FOR   PRODUCING   COUNTIES   IN   ILLINOIS. 
*COMPILED  FROM  BULLETIN  No.  2Q  ILL.  STATE  GEOL.  SURVEY. 


Table 
No. 

County 

Geolog- 
ical 
Seam 

Total 

Moisture 

Vol- 
atile 
Matter 

Fixed 
Carbon 

Ash 

Sul- 
phur 

Carbon 
Diox- 
ide 

B.t.u. 

"Unit 
Coal" 

1 

Bureau 

2  N 

16.27 

38.35 

38.00 

7.38 

2.93 

.89 

10883 

Dry 

45.80 

45.39 

8-81 

3.50 

1.40 

12997 

14477 

1 

Christian 

1  C 

11.31 

38.89 

40.94 

8-86 

2.35 

.43 

11602 

Dry 

43.85 

46.16 

9.99 

2.65 

.48 

13081 

14717 

3 

Clinton 

6  S 

12.62 

37.08 

40.10 

10.20 

3.90 

.66 

10796 

Dry 

42.45 

45-90 

11.67 

4.46 

.75 

12355 

14290 

4 

Franklin 

6.8 

9.04 

34.62 

47.78 

8.56 

1.45 

.44 

11837 

Dry 

38-06 

52.53 

9.41 

1.59 

.48 

13013 

14538 

5 

Fulton 

5  N 

16.16 

36-27 

37.09 

10.48 

3.14 

1.33 

10363 

Dry 

43.26 

44.24 

12.50 

3.74 

1.59 

12361 

14416 

6 

Gallatin 

5  S 

4.30 

35.93 

49.08 

10.69 

3.79 

.24 

12616 

Dry 

37.54 

51.29 

11.17 

3.96 

.25 

13183 

15109 

7 

Gallatin 

6  S 

7.54 

34.96 

45.68 

11.82 

4.34 

.23 

11916 

Dry 

37.81 

49.41 

12.78 

4.70 

.25 

12888 

15136 

8 

Jackson 

2  S 

9.28 

33.98 

51-02 

5.72 

1.29 

.29 

12488 

Dry 

37.46 

56.24 

6.30 

1.42 

.32 

13765 

14818 

9 

Jackson 

6  S 

8.96 

34.44 

46.40 

10.20 

2.65 

.40 

11609 

Dry 

37.83 

50.97 

11.20 

2.91 

.44 

12751 

14608 

10 

La  Salle 

2  C 

15.70 

39.54 

36.17 

8.59 

3.48 

•  96 

10731 

Dry 

46.91 

42.89 

10.20 

4.12 

1.15 

12728 

14444 

11 

La  Salle 

5  C 

14.76 

41.33 

34.26 

9.65 

3.38 

•  61 

10692 

Dry 

48.49 

40.19 

11.32 

3.97 

.71 

12543 

14397 

12 

La  Salle 

7  C 

13.56 

40.87 

37.80 

7.77 

3-68 

.17 

11347 

Dry 

47.28 

43.73 

8.99 

4.26 

.20 

13127 

14685 

13 

Logan 

5  C 

14.20 

37.19 

37.44 

11.37 

3.34 

1.42 

10490 

Dry 

43-35 

43.40 

13.25 

3.89 

1.66 

12226 

14400 

14 

Macon 

5  C 

14.15 

36.68 

?8-83 

10.34 

3.57 

.52 

10661 

419 

Dry 

42.73 

45.23 

12.04 

4.16 

.60 

12418 

14 

15 

Macoupin 

6  C 

13.88 

38.20 

37.75 

10.17 

4.31 

.34 

10657 

Dry 

44.36 

43-83 

11.81 

5.00 

.39 

12875 

14349 

16 

Madison 

6  S 

13.47 

38-59 

38-03 

9.91 

4.22 

.42 

10760 

Dry 

44.60 

43.95 

11.45 

4.88 

.49 

12435 

14370 

17 

Marshall 

2  N 

15.10 

39-06 

38.68 

7.16 

2-79 

.48 

11315 

Dry 

46.01 

45-56 

8.43 

3-23 

.56 

13327 

14796 

18 

Marion 

6  8 

10.79 

37.53 

40.46 

11.22 

3.96 

.45 

11069 

Dry 

42.07 

45-35 

12.58 

4.44 

.    -51 

12408 

14511 

19 

Menard 

5  C 

17.33 

35.88 

38.62 

8.17 

3.44 

.50 

10499 

Dry 

43.40 

46.72 

9.88 

4.16 

.60 

12700 

14478 

20 

Mercer 

1  W 

15.58 

39.17 

35-80 

9.45 

4.69 

.53 

10673 

Dry 

46.40 

42.41 

11.19 

5.55 

.63 

12643 

14546 

21 

Montgomery 

6  C 

14.15 
Dry 

36-88 
42.96 

39.14 
45.59 

9.83 
11.45 

3.84 
4.47 

.70 

.83 

10642 
12396 

14290 

22 

Moult  rie 

6  C 

6-83 
Dry 

39.15 
42.02 

42.32 
45-42 

11.70 

12.56 

4.02 
4.31 

.57 
.61 

11877 
12748 

14882 

23 

Peoria 

5  C 

14.96 

36-65 

36-99 

11.40 

3.26 

1.50 

10506 

Dry 

43.10 

43.49 

13-40 

3-83 

1.77 

12354 

14614 

24 

Perry 

6  C 

9.92 
Dry 

32.72 
36.81 

46.97 
52.15 

10.39 
11.53 

.92 
1.02 

.25 

.28 

11335 
12583 

14407 

25 

Perry 

6  W 

11.00 

36.75 

41.97 

10.28 

3.36 

.56 

11087 

Dry 

41.29 

47.16 

11.55 

3.78 

.63 

12457 

14359 

26 

Randolph 

6  S 

11.13 
Dry 

37.28 
41.95 

40.14 
45.17 

11.45 
12.89 

4.24 

4.77 

.58 
.65 

10855 
12214 

14351 

27 

Saline 

5  S 

6.92 

35.44 

49.06 

8-58 

3.76 

.39 

12314 

Dry 

38.08 

52.70 

9-22 

4.04 

.42 

13229 

14794 

28 

Sangamon 

5  C 

14.35 
Dry 

37.30 
43.55 

37-57 
43-86 

10.78 
12.59 

4.16 

4.86 

.59 
.69 

10555 
12323 

14415 

29 

St.  Clair 

6  S 

11.25 

39-57 

38-39 

10.79 

3.99 

.63 

11028 

Dry 

44.59 

43.26 

12.15 

4.50 

.71 

12426 

14457 

30 

Tazewell 

5  C 

14.38 

37.74 

38.23 

9.66 

3.10 

1.20 

10809 

Dry 

44.08 

44.65 

11.28 

3.62 

1.40 

12624 

14496 

31 

Vermilion 

6  C 

14.45 
Dry 

35.88 
41.94 

40-33 
47.14 

9-34 
10.92 

2.55 
2.98 

.75 

.88 

10920 
12764 

14575 

32 

Vermilion 

7  C 

12.99 

38-28 

38.75 

9.98 

2.93 

.56 

11143 

Dry 

44.00 

44.53 

11.47 

3.37 

.64 

12807 

14740 

33 

Williamson 

6  S 

9.31 

33.38 

48.90 

8.41 

1.54 

.36 

11913 

Dry 

36.81 

53.92 

9.27 

1.70 

.40 

13136 

14655 

COAL  CONTRACTS  61 

PURCHASE  AND  SALE  OP  COAL  UNDER  SPECIFIC ATIONJ 

Present-day  tendencies  relating  to  the  basis  for  coal  contracts  are 
reflected  in  the  following  quotations: 

When  a  proper  sample  of  the  coal  is  secured,  the  chemical  analyses  and  calori- 
meter determinations  for  B.tu.  are  a  better  guide  to  the  value  of  the  coal  than 
are  one  or  two  boiler  tests  for  the  same  purpose.2 

The  purchase  of  coal  under  specification  is  as  advantageous  as  a  definite  under- 
standing regarding  the  quality  and  other  features  of  any  other  product,  or  of  a 
building  operation  or  engineering  project.  The  man  who  buys  under  specification 
gets  what  he  pays  for  and  pays  for  what  he  gets.3 

The  heating  value  expressed  in  British  thermal  units  per  pound  is 
the  most  direct  measure  of  the  value  of  coal.  Contracts  made  on  what 
is  termed  the  "heat-unit  basis"  provide  therefore  that  the  amount  of 
money  paid  shall  be  in  direct  proportion  to  the  number  of  heat  units 
delivered.  It  is  evident  that  the  number  of  heat  units  varies  inversely 
with  the  quantity  of  ash  and  moisture.  That  the  bidder  should  be  thor- 
oughly familiar  with  these  factors  in  their  application  to  the  coal  which 
he  proposes  to  furnish  is  self-evident.  A  thorough  understanding  of  the 
methods  of  awarding  contracts  is  also  essential  to  the  dealer  who  pro- 
poses to  enter  bids  on  a  competitive  basis. 

Use  of  a  Double  Standard  of  Reference: — The  cost  of  a  given  lot 
of  coal  must  be  based  upon  the  weight  of  the  material.  The  sample 
taken  should  represent  the  coal  "as  delivered,"  and,  as  already  empha- 
sized, moisture  changes  in  the  sample  are  to  be  carefully  guarded 
against.  Variations  in  quality  are  taken  into  account  by  varying  the 
price  per  ton  directly  in  proportion  to  the  number  of  heat  units  deliv- 
ered. In  the  award  of  contracts  and  in  computations  for  payment, 
therefore,  the  calculations  are  based  upon  the  heat  units  per  pound  in 
the  coal  "as  delivered." 

Concerning  the  ash,  if  there  were  no  other  effect  produced  by  ash 
variations  than  a  corresponding  variation  in  the  heat  units  then  no  fur- 
ther account  would  be  taken  of  that  constituent  since  it  would  be  taken 
care  of  in  the  calculations  involving  the  heat  units.  However,  on  ac- 
count of  the  expense  in  handling,  and  because  of  a  lowering  of  efficiency 
resulting  from  excessive  ash,  an  additional  modification  in  price  is  made 
for  this  constituent.  For  greater  convenience  where  comparisons  are 
involved  and  to  eliminate  the  moisture  variable,  it  is  found  preferable 

1Adapted  from  Illinois  State  Geological  Survey.    Bulletin  29.    By  S.  W.  Parr, 

1914- 

2The  Purchase  of  Coal :  The  Arthur  D.  Little  Inc.  Laboratory  of  Engineer- 
ing Chemistry,  pages  10  and  n,  1909. 

3Pope,  G.  S.,  Purchase  of  coal  by  the  government  under  specifications :  U.  S. 
Geol.  Survey  Bull.  428,  page  10,  1910. 


62  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

to  refer  the  ash  values  to  the  "dry-coal"  basis.  This  involves  the  use 
of  a  double  standard  of  reference;  the  heat  units  are  referred  to  the 
"wet"  or  "as-received"  basis  and  the  ash  is  referred  to  the  "dry"  or 
'  *  moisture-free ' '  basis. 

The  methods  of  applying  the  various  conditions  involved,  in  the  pur- 
chase of  coal  by  the  Illinois  State  Board  of  Administration,  are  given  as 
follows : 

Bids  and  Awards: — (1).  Bidders  are  required  to  specify  their  coal 
offered  in  terms  of  British  thermal  units  "as-received,"  but  ash  is  speci- 
fied on  the  "dry-coal"  basis.  These  values  become  the  standards  for 
the  coal  of  the  successful  bidder. 

(2).  In  order  to  compare  bids,  all  proposals  are  adjusted  to  a  com- 
mon basis.  The  method  used  is  to  merge  all  three  variables — ash,  calorific 
value,  and  the  price  bid  per  ton — into  one  figure.  This  figure  will  be 
the  cost  in  cents  of  1,000,000  British  thermal  units  and  is  derived  as 
follows : 

(a).  All  bids  are  adjusted  to  the  same  ash  percentage  by  selecting 
as  the  standard  for  comparison  the  proposal  that  offers  coal  containing 
the  highest  percentage  of  ash.  Each  1  per  cent  of  ash  content  below 
that  of  this  standard  will  be  assumed  to  have  a  positive  value  of  2  cents 
per  ton,  and  accordingly  the  price  will  be  decreased  2  cents,  which  is  the 
amount  of  premium  allowed  under  the  contract  for  1  per  cent  less  ash 
than  the  standard  established  in  the  contract.  Fractions  of  a  per  cent 
will  be  given  proportional  values.  The  adjusted  bids  will  be  figured  to 
the  nearest  tenth  of  a  cent. 

(b).  On  the  basis  of  the  adjusted  price,  allowance  will  then  be 
made  for  the  varying  heat  values  by  computing  the  cost  of  1,000,000 
British  thermal  units  for  each  coal  offered.  This  determination  will  be 
made  by  multiplying  the  guaranteed  British  thermal  units  per  pound  by 
2,000  and  dividing  the  product  by  1,000,000.  This  factor  gives  the  guar- 
anteed number  of  million  units  per  ton  of  delivered  coal.  Dividing  the 
adjusted  price  as  found  under  (a)  by  this  factor  gives  the  cost  per 
million  heat  units. 

A  convenient  form  for  tabulating  bids  to  indicate  the  various  fac- 
tors entering  into  the  final  computation  of  cost  is  shown  below. 


AWARDING  OF  CONTRACTS 


63 


TABLE  XVI 
CONVENIENT  FORM  FOR  TABULATING  BIDS 


No, 

Joal  offered 

Guarantees 

Price  per  ton  2000  Ibs. 

Computed 
cost  in  cents 
per  1,000,000 
B.  t.  u. 

If   (b) 

Ash  in 
"dry 
coal" 
(per- 
cent) 

B.  t.  u. 
"as  re- 
ceived" 

As 
bid 

As  adjust- 
ed for  ash 

IT  (a) 

A 
B 
C 

Vermilion  Co. 
Screenings 

17 
'16 
14 

10300 
10400 
12500 

1.50 
1-35 

2.OO 

1.50 
1-33 
1.94 

7-3 
6.4 
7.8 

Sangamon  Co. 
Screenings 

Williamson  Co. 
Screenings 

Price  and  Payment: — Payment  for  coal  specified  in  the  proposal 
will  be  made  upon  the  basis  of  the  price  therein  named,  which  has  been 
corrected  for  variations  in  heating  value  and  ash  from  the  standard 
specified  in  the  contract,  as  follows: 

(a).  Considering  the  guaranteed  heat  units  on  the  "as-received" 
basis,  the  correction  in  price  will  be  a  proportional  one  and  is  determined 
by  the  following  formula : 


B.t.u.,  delivered 
B.t.u.,  guaranteed 


X  bid  price  =  price  corrected  for  B.t.u. 


The  correction  is  figured  to  the  nearest  tenth  of  a  cent. 

(b).  For  all  coal  that  by  analysis  contains  less  ash  on  a  dry-coal 
basis  than  the  percentage  guaranteed,  a  premium  of  2  cents  per  ton  for 
each  whole  per  cent  less  will  be  paid.  An  increase  in  the  ash  content 
of  2  per  cent  above  the  standard  established  by  the  contractor  is  toler- 
ated without  exacting  a  penalty.  "When  this  excess  is  greater  than  2 
per  cent,  deductions  are  made  in  accordance  with  the  following  table: 


64  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC 

TABLE  XVII 
SHOWING  DEDUCTIONS  FOR  EXCESS  ASH* 


Ash  as 
estab- 
lished 
in  pro- 
posal 

No 

deduc- 
tion for 
limits 
below 

Cents  per  ton  to  be  deducted 

Maxi- 
mum 
limits 
for  ash 

2 

4 

7 

12 

18 

25 

35 

Percentage   of  ash  in  "dry  coal" 

Percent 
5  
6  

7 

7 
8 

9 

10 

ii 

12 

13 
H 
15 

16 

17 
18 

iQ 

20 

7-8 
8-9 
9-10 

IO-II 

11-12 
12-13 

13-14 
14-15 
15-16 
I6-I7 
I7-I8 
I8-I9 
19-20 
20-21 

8-9 
9-10 

IO-II 
11-12 
12-13 
13-14 

14-15 
I5-I6 
I6-I7 
I7-I8 
I8-I9 
19-20 
20-21 
21-22 

9-10 

IO-II 
II   12 

IO-II 
I.I-I2 
12-13 

13-14 
14-15 
15-16 

17  18 

11-12 

12-13 

13-14 

1  14-15 
I5-I6 
I6-I7 
I7-I8 
18-19 
19-20 
2O-2I 
21-22 
22-23 

12-13 
13-14 
14-15 
I5-I6 
I6-I7 
I7-I8 

I8-I9 
I9-2O 
2O-2I 
21-22 

13-14 
14-15 
15-16 

16-17 
17-18 

12 

13 
14 
14 
15 
16 

16 
17 
18 
19 
19 

20 
21 

22 

8 

12-13 
13-14 
14-15 

m  16 

10  

ii 

12 

16-17 

17-18 
18-19 

13  
14 

18-19 
19-20 

20-21 
21-22 
22-23 

JC 

19  20 

16 

20-21 
21-22 
22-23 

17-  
18  

As  an  example  of  the  method  of  determining  the  deduction  in  cents 
per  ton  of  coal  containing  ash  exceeding  the  standard  by  more  than  2 
per  cent,  suppose  coal  delivered  on  a  contract  guaranteeing  10  per  cent 
ash  on  the  "dry-coal"  basis  shows  by  analysis  between  14.01  and  15  per 
cent  (both  inclusive),  or,  for  instance,  14.55  per  cent,  the  deduction  ac- 
cording to  the  table  is  1  cents  per  ton  (reading  to  the  right  on  line  be- 
ginning with  10  per  cent  on  the  extreme  left,  which  in  this  case  is  the 
standard,  to  the  column  containing  "14.01-15,"  the  deduction  at  the  top 
of  this  column  is  seen  to  be  7  cents). 

NOTE — If  the  ash  standard  is  an  uneven  percentage,  the  table  will 
be  revised  in  order  to  determine  deductions  on  account  of  excessive  ash. 
For  example,  if  the  ash  standard  is  6.53  per  cent,  each  percentage  value 
beginning  with  6  in  the  left-hand  column  and  all  figures  in  the  line  read- 
ing to  the  right  of  6  will  be  increased  by  0.53.  There  would  be  no  deduc- 

*Bulletin,  378,  United   States  Geological   Survey,   Results  of  Purchasing  Coal 
under  Government  Specifications. 


COMBUSTION  OF  COAL  65 

tion  then  in  the  price  of  ash  in  delivered  coal  up  to  and  including  8.53 
per  cent,  whereas  for  coal  having  an  ash  content,  for  instance,  between 
11.54  and  12.53  per  cent  the  deduction  would  be  12  cents  per  ton. 

The  Formulation  of  Proposals: — The  coal  operator  should  know 
what  guarantees  he  can  maintain  in  making  up  his  bid.  The  purchaser 
should  be  able  to  determine  the  likelihood  of  the  operator  being  able  to 
fulfill  his  guarantee  without  excessive  penalties.  Where  unit  coal  values 
are  known  for  a  particular  mine  or  district  this  information  is  a  simple 
matter  of  calculation  and  has  already  been  explained  on  p.  52.  The 
Table  No.  XV  of  average  unit  values  for  the  producing  counties  will 
furnish  the  initial  data. 

THE  COMBUSTION  OF  COAL 

General  Principles: — The  difficulties  attending  the  complete  com- 
bustion of  bituminous  coal  are  directly  related  to  the  volatile  matter 
present.  The  showing  of  large  volumes  of  smoke,  therefore,  is  a  sure 
sign  of  serious  loss  of  the  fuel  constituents.  The  underlying  principles 
furnish  a  sufficient  explanation  for  the  losses  which  accompany  heavy 
smoke.  A  brief  enumeration,  therefore,  is  here  given: 

(a)  At  temperatures  below  750°F  about  one-half  of  the  total  vola- 
tile matter  of  bituminous  coal  is  discharged. 

(b)  The  first  distillates  at  these  lower  temperatures  are  composed 
chiefly  of  the  so-called  heavy  hydrocarbons,  ethylene,  propylene,  ben- 
zene, etc.,  including  some  compounds  which  are  light  oils  at  ordinary 
temperature. 

(c)  Under  the  most  favorable  conditions  it  is  difficult  to  burn  these 
compounds  without  producing  a  smoky  flame,  a  prerequisite  being  a 
much  larger  mixture  of  air  than  that  required  for  the  distillates  which 
come    off    at    the    higher    temperatures,    mainly    methane    (CH4)    and 
hydrogen. 

(d)  A  high  percentage  of  moisture,  which  is  also  discharged  simul- 
taneously with  the  heavy  hydrocarbons,  accentuates  the  difficulty  by 
sudden  expansion  into  steam  and  consequent  displacement  of  air,  as 
well  as  by  lowering  the  temperature  of  the  combustion  chamber  while 
the  process  of  vaporization  is  proceeding. 

From  this  enumeration,  it  is  evident  that  to  discharge  these  first  dis- 
tillates into  a  relatively  cooler  zone  emphasizes  the  unfavorable  condi- 
tions for  combustion  and  results  also  in  a  condensation  of  some  of  the 
compounds,  all  of  which  is  made  evident  by  the  appearance  of  dense 
volumes  of  smoke.  This  is  always  the  result  with  house-heating  appli- 
ances and  is  more  or  less  evident  with  all  steam-generating  devices  which 
are  fired  intermittently. 

The  mechanical  or  physical  features  essential  to  smokeless  combus- 
tion are  now  well  understood  as  the  result  of  the  elaborate  investigations 


66  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

carried  on  by  Mr.  W.  L.  Abbott  and  Mr.  A.  Bement  at  the  Chicago  Edi- 
son plant.  The  two  fundamental  elements  involved  are: — First,  a  con- 
tinuous accession  of  fuel  by  some  system  of  automatic  stoking;  and,  sec- 
ond, the  discharge  of  the  volatile  products  into  a  highly  heated  combus- 
tion zone  for  accomplishing  both  the  necessary  admixture  of  air  and  the 
completion  of  the  oxidation  processes. 

STORAGE,  WEATHERING,  AND  SPONTANEOUS  COMBUSTION 

Deterioration: — Coal  is  subject  to  deterioration  from  the  time  of 
breaking  out  at  the  mine  until  used.  These  losses,  however,  are  rela- 
tively small.  A  sudden  drop  occurs  in  the  first  week  or  two,  due  no 
doubt  to  the  liberation  of  certain  of  the  hydrocarbons.  Subsequent 
losses  are  more  largely  due  to  the  absorption  of  oxygen  and  the  forma- 
tion of  humic  compounds  which  are  part  of  the  subsequent  coal  texture. 
The  cut  shown  herewith  is  typical  and  illustrates  the  kind  and  amount 
of  the  losses  over  the  space  of  one  year's  storage. 

Perhaps  even  more  serious  than  the  loss  by  weathering  is  the  disin- 
tegration or  slaking  which  takes  place,  whereby  the  coal  is  reduced  in 
size.  It  is  thus  rendered  more  difficult  to  maintain  a  proper  circulation 
of  air  through  the  fuel  bed.  The  matter  of  weathering  is  discussed  in 
detail  in  Bulletin  No.  38  of  the  Illinois  Engineering  Experiment  Station. 

Spontaneous  Combustion: — All  coals  of  the  bituminous  type  are 
subject  to  spontaneous  combustion.  A  detailed  study  of  the  causes  has 
been  made  in  Bulletin  No.  46  of  the  Illinois  Engineering  Experiment 
Station.  Briefly  summarized,  they  are  as  follows : 

1.  The  oxidation  of  coal  is  continuous  over  a  wide  range  of  time 
and  conditions,  and  begins  with  the  freshly-mined  coal  at  ordinary  tem- 
peratures.    A  number  of  oxidation  processes  are  involved  which  are 
more  or  less  distinct  in  character,  some  being  relatively  slow  and  moder- 
ate in  form,  while  others  are  rapid  and  vigorous  in  their  action. 

2.  In  general,  we  may  say  that  for  a  given  coal  a  point  exists  as 
indicated  by  the  temperature,  below  which  oxidation  is  not  ultimately 
destructive  and  its  continuance  is  dependent  upon  certain  accessory  con- 
ditions which,  if  withdrawn,  the  oxidation  ceases.     On  the  other  hand, 
above  this  critical  point,  which  is  best  indicated  by  temperatures,  oxida- 
tion is  ultimately  destructive  and  is  characterized  by  the  fact  that  it 
does  not  depend  for  its  continuance  upon  external  conditions,  but  is  self- 
propelling  or  autogenous. 

3.  The  point  of  outogenous  oxidation,  while  varying  for  different 
conditions,  may  be  indicated  by  temperatures  of  the  mass  ranging  from 
200°  to  275 °C,  depending  to  a  great  extent  upon  the  fineness  of  division. 
The  phenomenon  of  fire  or  actual  kindling  does  not  occur  until  a  much 
higher  temperature  is  reached,  usually  beyond  350° C. 


SPONTANEOUS  COMBUSTION  67 

4.  The  temperature  at  which  autogenous  oxidation  begins  is  the 
sum  of  numerous  temperature  components,  each  one  of  which,  either  be- 
cause of  its  own  contribution  to  the  total  heat  quantity  or  because  of  its 
function  as  a  booster  for  chemical  activities,  must  be  looked  upon  as  a 
dangerous  factor  tending  directly  to  the  ultimate  result  of  active  com- 
bustion throughout  the  mass.  An  enumeration  of  the  more  important 
elements  which  contribute  towards  this  end  are  the  following: 

a. — External  Sources  of  Heat: — Oxidation,  especially  of  the  lower 
or  moderate  form,  is  greatly  accelerated  and  in  certain  phases  directly 
dependent  upon  an  increase  of  temperature.  What  may  be  termed  ex- 
ternal or  physical  sources  of  heat,  and  thus  presumably  avoidable,  are 
suggested  by  the  following: 

(1)  Contact  of  the  mass  with  steam  pipes,  hot  walls  or  floors  un- 
der which  are  placed  heat  conduits  of  any  sort. 

(2)  The  heat  of  impact  or  pressure  due  to  the  method  of  unload- 
ing or  to  the  depth  of  piling. 

(3)  Climatic  or  seasonal  temperature  at  the  time  of  storage. 

(4)  The  direct  absorption  of  heat  from  the  sun  or  from  reflecting 
surfaces. 

~b. — Fineness  of  Division: — Coal  in  a  fine  state  of  division  presents 
a  very  much  larger  surface  and  brings  a  much  larger  quantity  of  react- 
ing substances  in  contact  with  oxygen  than  when  in  solid  masses.  Un- 
der these  conditions,  with  a  condensation  or  accumulation  of  relatively 
large  amounts  of  oxygen  immediately  surrounding  or  in  contact  with 
the  particles  of  carbonaceous  matter,  the  circumstances  are  exceedingly 
favorable  for  rapid  oxidation  upon  the  arrival  of  the  mass  to  a  suitable 
temperature.  But,  more  especially  does  this  fineness  of  division  facili- 
tate the  initial  form  of  oxidation  described  under  c  below. 

c. — Easily  Oxidizable  Compounds: — An  initial  stage  of  oxidation 
exists  in  bituminous  coals  which  does  not  result  in  the  formation  of 
carbon  oxide.  There  are  present  in  coals  of  this  type  unsaturated  com- 
pounds which  have  a  marked  avidity  for  oxygen  at  ordinary  tempera- 
tures, the  products  being  humic  acid  or  other  fixed  constituents  of  the 
coal  texture.  Coals  vary  widely  in  this  matter  and  it  has  been  proposed 
by  some  to  regard  this  property  as  an  index  of  the  liability  to  sponta- 
neous combustion.  It  is,  however,  very  largely  dependent  upon  the 
freshness  of  the  coal  and  upon  the  fineness  of  division,  (See,  under  & 
above),  and  should  be  looked  upon  as  a  contributing  factor,  though  in 
coals  of  the  Illinois  type  at  least,  with  their  high  per  cent  of  sulphuf , 
this  action  should  doubtless  be  considered  second  in  importance  to  that 
of  iron  pyrites. 

d. — Iron  Pyrites: — The  presence  of  sulphur  in  the  form  of  iron 
pyrites  is  a  positive  source  of  heat  due  to  the  reaction  between  sulphur 
and  oxygen.  Here  again  rapidity  of  oxidation  is  directly  dependent 


68  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

upon  fineness  of  division.  Since  coals  of  the  Mid-Continental  field  espe- 
cially have  a  much  higher  earthy  or  ash  content  in  the  fine  material,  and 
since  iron  pyrites  is  a  large  component  of  this  substance,  it  follows  that 
the  presence  of  dust  or  duff  in  all  coals  of  the  Illinois  type  is  a  positive 
source  of  danger.  Since  coals  of  the  Illinois  or  Mid-Continental  field 
have  in  the  larger  number  of  cases  iron  pyrites  averaging  over  5  per 
cnt  or  as  sulphur  above  2y2  per  cent,  the  heat  increment  from  the  oxida- 
tion of  only  1/5  of  this  material  is  sufficient  to  raise  the  temperature  of 
the  mass  approximately  70°,  assuming  that  there  is  no  loss  by  radiation. 
Under  usual  conditions,  and  especially  considering  the  greatly  accel- 
erated rate  of  chemical  activity  accompanying  a  rise  of  temperature,  this 
oxidation  may  proceed  with  such  rapidity  that  the  heating  up  of  the 
mass  will  be  but  little  affected  by  the  loss  of  heat  due  to  radiation,  ex- 
cept in  relatively  shallow  piles.  Coals  of  low  sulphur  content  or  such  as 
do  not  have  sulphur  greatly  in  excess  of,  say  1-%  per  cent  are  popularly 
supposed  to  be  immune  from  heating,  but  no  method  of  selection  or 
hand-picking  at  the  mine  can  eliminate  all  of  the  iron  pyrites.  Lumps 
of  coal,  to  all  outward  appearance  of  good  texture,  may  have  nodules  or 
detached  bands  of  iron  pyrites.  These  become  centers  of  activity  and 
with  the  addition  of  moisture  such  coal  will  have  many  scattered  spots 
where  heating  begins.  If  fine  coal  is  mixed  in  with  the  coarse,  the  diffi- 
culty is  accentuated.  Doubtless  a  complete  separation  of  fine  and  lump 
material  in  such  cases  would  lessen  the  danger. 

e. — Moisture: — Moisture,  while  essential  to  pyritic  oxidation,  is 
given  separate  mention  because  its  importance  is  apt  to  be  underesti- 
mated. Any  coal  with  pyritic  conditions  as  above  mentioned  will  be  fa- 
cilitated in  that  action  by  moisture.  It  is  to  be  noted  in  this  connection 
that  the  normal  water  content  or  vein  moisture  of  coals  in  this  central 
region  is  rarely  below  10  per  cent  and  ranges  usually  from  12  per  cent 
to  15  per  cent.  The  presence  of  such  water  must  be  borne  in  mind  in 
considering  the  likelihood  of  chemical  activity  on  the  part  of  the  pyrites 
present. 

/. — The  Oxidation  of  Carbon  and  Hydrogen: — A  third  stage  of  oxi- 
dation of  the  carbonaceous  material  exists  by  reason  of  the  property  of 
certain  of  the  hydrocarbon  compounds  of  coal  to  oxidize  with  the  forma- 
otni  of  C02  and  H20  at  temperatures  in  excess  of  120°  to  140°.  Though 
this  type  of  oxidation  does  not  take  place  appreciably  at  ordinary  tem- 
peratures, it  must,  be  looked  upon  as  an  exceedingly  dangerous  stage  in 
the  process  of  oxidation,  owing  to  the  very  much  higher  quantity  of  heat 
which  is  discharged  by  the  oxidation  of  carbon  and  hydrogen;  so  that 
the  temperature  of  autogenous  action,  though  ordinarily  occurring  at  a 
higher  point  by  100°  or  more,  may  be  quickly  attained  as  a  result  of  this 
form  of  oxidation.  Any  initial  heat  increments,  therefore,  which  threaten 


WEATHERING  OF  COAL  69 

to  bring  the  chemical  activities  along  to  the  point  where  the  oxidation 
processes  invade  the  carbonaceous  material  in  this  manner  must  be 
looked  upon  as  dangerous.  For  example,  any  of  the  initial  or  contribu- 
tory processes  which  result  in  raising  the  temperature  of  the  mass  50° 


i  J_ 


EXPOSED  BINS 
COVERED   BINS—- 
UNDER  WATER  — 


FIG.  13.    VERMILION  COUNTY,  ILLINOIS,  SCREENINGS  SHOWING  THE  LOSS  IN  HEAT 

VALUE  FOR  THE  FIRST  TWO  WEEKS,  AND  FOR  EACH  MONTH 

FOLLOWING  THROUGHOUT  THE  YEAR 

above  the  ordinary  temperature  would,  in  all  probability,  have  enough 
material  of  the  sort  involved  in  such  action  to  continue  the  activity  until 
another  50°  had  been  added,  which  would  thereby  attain  to  the  condition 
wherein  this  third  stage  of  oxidation  would  begin. 


70  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

g. — Autogenous  Oxidation: — The  fourth  stage  of  oxidation  may  be 
indicated  as  occurring  at  temperatures  above  200°  to  275°  and  differs 
from  the  previous  stages  in  that  the  action  is  autogenous  and  not  depend- 
ent upon  other  sources  of  heat  to  keep  up  the  reacting  temperature.  Ac- 
tivity in  this  stage  is  further  accelerated  by  the  fact  that  above  300°  the 
decomposition  of  the  coal  begins  which  is  exothermic  in  character, 
thereby  contributing  somewhat  to  a  further  increase  in  temperature. 
The  ignition  temperature  is  reached  at  a  point  still  further  along,  usually 
in  excess  of  300°  to  400°C. 

Storage  Methods: — The  above  formulation  of  the  various  stages  and 
types  of  oxidation  clearly  indicates  the  principles  which  must  be  ob- 
served in  any  attempt  at  the  prevention  of  spontaneous  combustion.  The 
following  enumeration,  therefore,  of  preventive  or  precautionary  meas- 
ures is  to  be  considered  as  suggestive  rather  than  complete  in  character : 

First,  The  avoidance  of  external  sources  of  heat  which  may  in  any 
way  contribute  toward  increasing  the  temperature  of  the  mass  is  a  first 
and  prime  essential. 

Second,  There  must  be  an  elimination  of  coal  dust  or  finely-divided 
material.  This  will  reduce  to  a  minimum  the  initial  oxidation  processes 
of  both  the  carbonaceous  matter  and  the  iron  pyrites.  These  lower  forms 
of  oxidation  are  to  be  looked  upon  as  boosters,  without  which  it  would 
be  impossible  for  the  more  active  and  destructive  activities  to  become 
operative. 

Third,  Dryness  in  storage  and  a  continuation  of  the  dry  state,  to- 
gether with  an  absence  of  finely-divided  material,  would  practically 
eliminate  the  oxidation  of  the  iron  pyrites.  The  drenching  down  with 
water  of  heating  piles,  where  the  sulphur  content  is  high  and  uniformly 
distributed,  accentuates  the  difficulty.  Where  pyritic  activity  is  local- 
ized in  spots  or  is  so  small  in  amount  as  to  reach  a  possible  exhaustion, 
the  drenching  with  water  may  check  the  heating  or  prolong  the  action 
so  that  oxidation  of  the  carbonaceous  matter  does  not  get  under  way  to 
a  serious  extent.  In  such  cases,  however,  there  is  no  ultimate  safety  ex- 
cept in  the  removal  of  the  heated  zones. 

Fourth,  The  submergin  of  coal,  it  is  very  evident,  will  eliminate 
all  of  the  elements  which  contribute  towards  the  initial  temperatures. 
As  to  its  industrial  practicability,  it  can  best  be  determined  by  actual 
experience. 

Other  processes  may  be  suggested  by  the  formulation  of  the  princi- 
ples involved.  Such,  for  example,  would  be  the  distribution  throughout 
the  coal  of  cooling  pipes  through  which  a  liquid  would  circulate  having 
a  lower  temperature  than  the  mass.  This  would  serve  to  carry  away 
any  accumulation  of  heat  and  confine  the  oxidation  to  the  lower  stages 
only.  On  the  contrary,  the  proposition  sometimes  made  to  provide  cir- 


RELATIVE  GAS  VOLUMES  71 

dilating  passages  for  the  transmission  of  air  currents  is  of  questionable 
value,  since  it  may  result  in  the  contribution  of  more  heat  by  the  added 
accessibility  of  oxygen  than  will  be  carried  away  by  the  movement  of 
the  air. 

CHAPTER   III 
FLUE    GAS 

Gas  Volumes: — Air  has  the  composition  by  volume  of  20.78  per 
cent  of  oxygen  and  79.22  per  cent  of  nitrogen.  In  passing  through  the 
fuel  bed  the  nitrogen  is  unchanged,  being  chemically  inactive,  and  pro- 
ceeds into  the  flue  spaces  in  the  same  form  in  which  it  entered  the 
furnace.  The  oxygen,  on  the  contrary,  enters  into  chemical  reaction, 
combining  with  the  carbon  to  form  CO2  and  CO  and  with  the  hydrogen 
to  form  H20.  As  in  all  chemical  processes,  an  excess  of  the  reagent 
must  be  present  in  order  to  accomplish  a  rapid  and  complete  reaction. 
There  will  always  be  found,  therefore,  in  the  flue  gases  a  very  consider- 
able amount  of  excess  or  unused  oxygen.  The  essential  constituents, 
therefore,  to  be  determined  in  the  analysis  of  flue  gases  are 

(1)  C02 

(2)  Oxygen 

(3)  CO 

(4)  Nitrogen  (by  diff.) 

In  the  combustion  of  carbon,  the  reaction  which  occurs  may  be 
represented  by  the  formula  C  -j-  O2  =  CO2.  This  means  that  for  each 
volume  of  oxygen  one  volume  of  CO2  results.  If,  therefore,  pure  carbon 
were  burned  and  the  exact  amount  of  air  were  supplied  to  completely 
represent  the  volumes  indicated  in  the  above  equation,  the  resulting  flue 
gas  would  be  composed  of  20.78  per  cent  of  C02  and  79.22  per  cent  of 
nitrogen.  This,  therefore,  would  represent  the  extreme  limit  of  theo- 
retical possibility  as  to  the  percentage  of  the  volume  of  CO,  in  such  a 
flue  gas.  However,  from  the  principal  already  stated  as  to  the  necessity 
of  an  excess  of  reagent,  the  rapid  and  complete  oxidation  of  the  carbon 
can  only  be  effected  by  having  an  excess  of  oxygen,  at  least  50  per  cent 
more  than  that  utilized  in  the  combustion,  and  even  at  this  ratio  the 
oxygen  would  begin  to  be  sufficiently  low  in  amount  to  result  in  the 
formation  of  a  very  considerable  quantity  of  CO.  From  actual  experi- 
ence it  would  seem  that  a  content  of  CO2  in  the  flue  gases  of,  say,  12 
per  cent  approaches  the  limit  of  practicability,  while  doubtless  from  8 
to  10  per  cent  of  CO2  would  represent  conditions  which  are  above  the 
average  in  practice. 

It  should  be  borne  in  mind  also  that  while  carbon  constitutes  the 
larger  part  of  the  fuel  content,  the  combustion  of  hydrogen  (which  on 


72  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

the  average  represents  from  3  to  4  per  cent  of  the  coal),  would  be  rep- 
resented by  the  formula 

2H2  +  O2  =  2H20. 

That  is,  one  volume  of  oxygen  results  in  two  volumes  of  water  vapor. 
Now,  since  in  the  process  of  analysis  the  water  vapor  condenses  and 
does  not  appear  in  the  results,  it  must  follow  that  the  nitrogen  which 
accompanied  the  original  oxygen  into  the  furnace  in  this  case  is  left 
alone  without  an  accompaniment  of  gaseous  product  corresponding  to 
the  C02  as  in  the  case  of  the  combustion  of  carbon.  To  this  extent, 
therefore,  the  ratio  of  theoretical  C02  in  the  flue  gases  is  diminished. 
From  these  considerations  it  will  appear  that  the  uses  that  may  be  made 
of  the  constituents  are : — First,  a  very  fair  estimate  of  efficiency  of  the 
firing  may  be  obtained  from  the  percentage  content  of  C02  in  the  flue 
gases.  If,  for  example,  it  is  known  that  for  the  boiler  setting  and  equip- 
ment of  a  given  furnace,  it  is  capable  of  carrying  on  combustion  to  an 
extent  which  will  be  represented  by  10  per  cent  of  CO2  in  the  flue 
gases,  then  when  the  flue  gases  show  only  5  per  cent  of  this  constituent, 
there  is  evidence  of  carelessness  in  firing  which  is  capable  of  correction. 
Calculations: — The  flue  gas  constiuents  and  temperatures  afford  a 
basis  f 01*, calculating  efficiencies  and  heat  losses.  Three  general  features 
are  usually  included  as  follows: 

(a)  The  number  of  pounds  of  air  entering  per  pound  of  fuel. 

(b)  The  ratio  of  air  entering  the  grate  to  the  air  used. 

(c)  The  loss  of  heat  passing  up  the  chimney. 

(a)  Pounds  of  Air  Entering  per  Pound  of  Coal: — The  gram 
molecule  of  any  gas,  that  is,  the  molecular  weight  of  the  gas  in  grams, 
has  a  definite  volume  and  is  the  same  for  all  gases;  namely,  22.4  liters 
at  standard  temperature  and  pressure.  For  example  44  grams  of  C02 
have  a  volume  of  22.4  L. ;  32  grams  of  O2  have  a  volume  of  22.4  L.,  etc. 
In  a  mixture  of  gases,  therefore,  the  weight  of  each  constiuent,  W, 
in  22.4  L.  equals  the  molecular  weight  X  the  percentage  present  thus : — 
(1)  W  =  mol.  wt.  of  component  X  per  cent. 

In  arriving  at  the  weight  of  air  entering  the  grate,  the  weight  of 
the  total  nitrogen  will  give  the  most  direct  factor  for  calculating  the 
air.    For  example,  making  use  of  equation  (1)  the  weight  of  nitrogen, 
W1,  in  a  gram-molecule-volume  would  be : 
W1  =  28  X  per  cent  N2 

In  order  to  refer  the  weight  of  nitrogen  present  to  a  unit  quantity 
of  fuel,  we  shall  need  to  determine,  first  the  amount  of  pure  carbon 
involved  in  the  production  of  the  unit  volume  of  flue  gas.  This  can  be 
readily  accomplished  by  deriving  the  weight  of  carbon  in  the  gas  and 
making  one  gram  of  carbon  the  unit  of  reference.  For  example,  12/44 
of  the  CO2  and  12/28  of  the  CO  present  is  carbon. 


CALCULATION  OF  RATIOS  73 

If  we  let  C  represent  the  weight  of  carbon  in  the  unit  volume,  then 

C  =  12/44  X  44  CO2  +  12/28  X  28  CO 
hence 

C  =  12  (C02  +  C0) 

If,  therefore,  C  represents  the  number  of  grams  of  carbon  which 
deliver  a  flue  gas  with  W1  grams  of  nitrogen,  then  the  weight  of  nitro- 

W1 

gen  per  gram  of  carbon  burned  is    — — -  or  in  terms  of  the  assigned 

\s 


values, 


(2)     W  -_?!!?! or       7N= 

V       /  -«  ci        /  /^i  /~\  i  /"*  /~\  \ 


12   (C02  +  CO)  3   (C02  +  CO) 

Assuming  for  illustration  a  chimney  gas  of  the  following  composition : — 

C02 10.  % 

Oo 8.  % 

CO" 5% 

N2 81.5% 

resulting  from  the  combustion  of  a  coal  having  70  per  cent  of  carbon 
exclusive  of  the  carbon  lost  in  the  ash.  Then  by  substituting  these 
values  in  equation  (1)  we  have: 

7    V    £1  ^ 

1 


3  X    (10  +  5) 

That  is,  18.11  grams  nitrogen  in  the  flue  gases  accompany  the  combus- 
tion of  1  gram  of  carbon.  Similarly  there  would  be  18.11  pounds  of 
nitrogen  in  the  flue  gases  from  1  pound  of  carbon,  and  for  a  coal  of 
70%  carbon  the  weight  would  be  .70  X  18.11  =  =  12.68  pounds  N2.  Since 
nitrogen  passes  through  the  furnace  unchanged  the  calculation  to  the 
equivalent  weight  of  air  entering  'is, — 

77    :    100    ::    12.68    :    x 
x  =  16.47 

Hence  the  weight  of  air  entering  per  pound  of  coal  is  16.47  pounds. 

(b)  Ratio  of  Air  Entering  to  Air  Used: — From  the  discussion 
under  (a)  the  weight  of  oxygen  per  pound  of  carbon  would  be  repre- 
sented by  the  expression,— 

32  O,  8  02 


(3)     W1  =  -  or 


12  (CO,  +  CO)  3  (CO2  +  CO) 


74  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

Substituting  the  values  indicated  under  (a)  we  have 

W1  =  8  X  8 =  2.03 

3   (10  +  .5) 

and  for  a  coal  having  70%  of  carbon  the  weight  would  be  1.42  pounds 
per  pound  of  coal.    Calculating  the  oxygen  to  the  equivalent  of  air, — 

23    :    100    ::    1.42    :    x 
x  =  6.17 

Hence  the  weight  of  air  passing  through  unused  is  6.17  pounds  per 
pound  of  coal. 

From  (a)  and  (b)  therefore 

Total  air  entering 16.47  pounds 

Air  unused  6.17       ' ' 

Air  used  10.30 

16.47 


10,30 


=  1.60     Eatio  of  air  entering  to  air  used 


(c)  The  Loss  of  Heat  Passing  Up  the  Chimney: — The  factors 
which  enter  into  the  calculation  of  heat  losses  in  chimney  gases  are  (1) 
the  weight  of  the  flue  gas  per  pound  of  fuel,  (2)  the  specific  heat  in 
B.t.u.  per  pound,  and  (3)  the  rise  in  temperature  or  difference  in  tem- 
peratures (t  -  t1)  between  the  entering  air  and  the  gases  as  they  leave 
the  furnace. 

(1)  The  weight  of  the  gas  per  pound  of  fuel  may  be  readily  de- 
rived from  the  formula  for  "W  as  developed  under  (a)  and  (b)  above. 
Letting  Wv  represent  the  weight  of  the  mixed  gases  per  pound  of  pure 
carbon,  then  by  a  similar  procedure  to  that  shown  in  equation  (2)  under 
(a)  and  equation  (3)  under  (b)  we  would  have  for  the  total  weight  of 
all  of  the  components  per  pound  of  carbon : 

w    =  11_C02  +  8  '0,  +  7  CO  +  7  N2 


3  (C02  +  CO) 

Or,  since  CO  +  N2  =  =  100  -  -  C02  -  -  02  this  expression  may  be  still 
further  simplified  to  read: 

w       _  4  C02  +  02  +  700 


3  (C02  +  CO) 

Assuming  the  coal  used  as  in  (a)  and  (b)  to  have  70  per  cent  of  carbon 
(the  carbon  of  the  ash  having  been  subtracted),  then  by  substituting  the 
percentage  values  for  the  chimney  gas  as  already  indicated  and  multi- 


CALCULATION  OF  HEAT  LOSSES  75 


W  -  ^  X  10  +  8  +  700   x  J0  _  16_62 


plying  by  .70  we  would  have  the  weight  of  gases  per  pound  of  fuel  : 
><  10  +  8  + 
3  (10  +  0.5) 

Therefore  for  (1) 

W  =  =  16.62  pounds  dry  gases  per  pound  of  fuel. 
(2)     The  specific  heats  of    the  various    components,  at    constant 
pressure  in  B.t.u.  per  pound,  calculated  for  the  interval  60°F  -  600°F, 

C02  =  0.222 

02  =  .217 
CO  =  .245 

N2  =  .2407 
H26  =  .4673 

From  which  it  appears  that  an  average  specific  heat  of  0.24  for  all 
the  constituents  exclusive  of  water  vapor  may  properly  be  applied. 
Assuming,  therefore,  the  (t  -  t1)  values  of  60°  entering  and  600°  leav- 
ing, we  have  a  total  loss  L  for  the  dry  gases  thus  : 

L  —  16.62  X  0.24  X  540 
L  =  2154  B.t.u. 

Assuming  a  heat  value  of  12,000  B.t.u.  for  the  coal  per  pound  as  fired, 
then  the  percentage  loss,  L1,  would  be,  — 

X  100 


12000 
L1  =  =  17.95  per  cent. 

Other  Losses:  —  In  obtaining  a  heat  balance  as  in  boiler  tests,  other 
heat  losses  are  taken  account  of.    They  include: 

A.  The  latent  heat  of  vaporization  of  moisture. 

B.  The  heat  of  the  water  vapor  passing  off  at  the  temperature 

of  the  chimney. 

C.  The  heat  combustion  of  carbon  to  CO,  instead  of  to  CO,. 

D.  The  unburned  carbon  in  the  ash. 

A.     The  water  from  which  the  loss  of  heat  is  calculated  is  made 
up  of 

(a)  The  total  hydrogen  of  the  coal  burning  to  H.,0,  that  is 

HX9. 

(b)  The  free  moisture  of  the  coal. 

(c)  The  moisture  of  the  air  as    indicated    by    the    relative 

humidity. 


76  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

The  sum  of  the  three  amounts  of  water  referred  to  the  unit  of  1 
pound  of  coal  multiplied  by  the  factor  for  the  latent  heat  of  vaporiza- 
tion represents  the  heat  loss  in  B.t.u.  per  pound  of  coal  thus : 

B.t.u.  loss  ] 

per  pound  f  =  wt.  of  H20  X  966 

of  coal        J 

B.  Having  found  the  weight  of  water  as  under  A,  the  heat  loss 
due  to  rise  in  temperature  from  room  temperature,  t,  to  212°,  and  from 
212°  to  temperature  of  flue  gases,  T,  is  found,  using  the  specific  heat 
factor  for  the  water  vapor, .of  0.467,  thus:— 

B.t.u.  loss  ] 

per  pound  }•  =  H,0  X  (212— t)  +  H20  X  0.467  X  (T— 212) 

of  coal        J 

C.  The  heat  loss  due  to  the  burning  of  carbon  to  CO  instead  of 
C02  is  found  by  multiplying  the  weight  of  carbon  thus  entering  into 
the  reaction  per  pound  of  coal,  by  the  difference  between  the  calorific 
value  of  carbon  burned  to  C02  and  carbon  burned  to  CO,  thus : — 

B.t.u.  loss  from  CO] 

per  pound  j>  =  Wt.  C.  in  CO  X  10150 

of  coal  J 

D.  The  loss  of  heat  due  to  combustible  matter  passing  through 
with  the  ash  unburned  is  found  by  determining  the  combustible  in  the 
ash  as  carbon,  c,  and  referring  it  to  the  total  refuse,  r,  in  its  proper  pro- 
portion, x,  to  the  ash,  a,  of  the  original  fuel  thus : 

C    :    r    ::    x    :    a 
Having  the  value,  x,  in  percentage  of  the  original  coal  as  fired,  then, — 

Heat  loss  per  pound  \  _  _ 

of  coal  from  unburned  carbon  j 

CHAPTER   IV 

LUBRICANTS. 

"Next  to  the  conservation  of  the  world's  fuel  supply  there  is  proba- 
bly no  subject  of  greater  importance  in  the  manufacturing  world  than 
the  control  of  waste  power  caused  by  imperfect  lubrication  and  needless 
friction.  *****  Archbutt  has  stated  that  of  the  10,000,000  h.p.  in 
use  in  the  United  Kingdom  of  Great  Britain  considerably  more  than  half 
this  amount,  40  to  80  per  cent  of  the  fuel,  is  spent  in  overcoming  fric- 


LUBRICANTS  77 

tion,  and  that  a  considerable  proportion  of  this  power  is  wasted  by  im- 
perfect or  faulty  lubrication."* 

Any  substance  made  use  of  for  the  lessening  of  friction  is  called 
a  lubricant.  By  its  use  the  surfaces  of  sliding  bodies  are  separated  by 
a  thin  film  which  permits  of  easier  movement  than  if  the  surfaces  were 
in  direct  contact.  Lubricants  must,  therefore,  vary  widely  for  the  dif- 
ferent kinds  of  work  involved.  For  example,  the  "body"  must  be  suited 
to  the  load.  Working  temperatures,  both  high  and  low,  must  be  pro- 
vided for.  Oxidizing  or  gumming  must  not  be  a  property  of  the  material, 
and  any  tendency  to  corrode  the  metal  surfaces  must  be  absent. 

Lubricants  are  derived  from  two  main  sources: 
First,  Oils  of  animal  or  vegetable  origin 
Second,  Mineral  oils. 

Animal  and  Vegetable  Oils: — All  oils  of  this  class  are  saponifiable. 
That  is,  they  are  compounds  of  fatty  acids  and  glycerine.  They  decom- 
pose to  a  considerable  extent  on  long  standing,  setting  free  the  fatty 
acids.  Many  vegetable  oils,  as  linseed  oil,  readily  oxidize,  forming  a 
gumming  substance.  Only  non-oxidizable  oils  are  suitable  for  lubrica- 
tion. Among  vegetable  oils  the  best  known  illustrations  are  olive  (sweet) 
oil  and  castor  oil.  Among  animal  oils,  lard  oil  is  perhaps  the  most 
common. 

Mineral  Oils: — These  oils  are  derived  from  petroleum  by  distilla- 
tion. They  will  not  saponify,  having  no  combination  of  fatty  acids, 
and  they  will  not  oxidize  to  form  "gumming"  compounds. 

The  compounding  of  oils  is  an  attempt  to  render  a  certain  oil  more 
effective  by  mixing  with  another  oil  having  slightly  different  properties. 
Thus,  mineral  oils  may  be  said  to  be  compounded  with  an  animal  oil  to 
impart  greater  body  or  viscosity  to  the  mixture ;  or,  a  vegetable  oil  with 
heavy  body  but  too  little  fluidity,  may  be  compounded  with  a  mineral 
oil  to  improve  its  property  in  that  direction.  Mineral  oils  are  often 
compounded  with  each  other  to  produce  certain  desired  properties. 
Greases  are  mixtures  of  heavy  oil  residues  or  vaseline-like  substances 
with  mineral  soap,  such  as  lime  soap,  to  the  extent  of  30  to  40  per  cent, 
thus  giving  a  mixture  of  great  body  for  heavy  machinery,  shafting, 
gears,  etc.  Finely  pulverized  mica  or  graphite  is  also  similarly  employed. 

For  high  temperature  service  the  problem  becomes  more  difficult. 
An  oil  must  be  selected  which  will  not  volatilize  at  the  high  temperature 
employed.  The  principal  tests  in  the  examination  of  oils  have  for  their 
purpose  the  development  of  these  various  properties; — for  example,  the 
viscosity  and  body  as  shown  by  the  viscometer,  and  specific  gravity,  the 
flash  point  for  high  temperature  use,  acid  or  saponification  number  to 

*C.  F.  Maberry,  Jour.  Ind.  and  Eng.  Chem.  II,  115.     1910. 


78  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

show  whether  or  not  the  oil  is  compounded  with  animal  or  vegetable 
material. 

Methods  for  testing  lubricating  ores,  therefore,  include  determina- 
tions for 

(a)  Viscosity 

(b)  Specific  gravity 

(c)  Flash  and  fire  temperatures 

(d)  Saponification  number 

Because  of  their  low  cost  and  the  ease  with  which  they  may  be  varied 
to  meet  the  different  conditions  as  to  load,  speed  and  temperature,  petro- 
leum and  the  products  which  may  be  derived  therefrom  have  come  to 
predominate  in  the  entire  field  of  lubricants. 

Hydrocarbons  of  the  general  type,  CnH2n+2  or  the  paraffin  series 
are  probably  best  suited  for  lubrication  purposes.  However,  because 
of  the  development  of  processes  for  distilling,  cracking,  and  mixing  it 
would  be  impossible  to  prescribe  a  chemical  composition  to  conform  to 
any  specific  type  of  carbon  compounds.  Doubtless  some  forms  are  more 
unstable  than  others  and  as  a  rule,  in  service  at  high  temperatures  as 
with  automobiles,  there  is  a  tendency  toward  decomposition  which  is 
almost  always  accompanied  by  the  formation  of  free  carbon.  Promoters 
of  petroleum  lubricants,  however,  who  claim  their  special  oils  are  with- 
out any  carbon  in  their  composition,  have  more  zeal  than  chemical  sense. 


PART  II 
LABORATORY  PROCESSES 

CHAPTER   V 

INTRODUCTORY 

Normal  Solutions: — If  the  reaction  between  one  solution  and  an- 
other can  be  gauged  exactly  as  to  the  "end  point",  that  is,  if  that  point 
can  be  noted  where  an  exact  balance  exists  between  the  two  reacting 
substances,  we  may  make  use  of  these  solutions  as  media  for  making 
chemical  measurements,  just  as  a  mechanic  uses  a  foot  rule  for  measur- 
ing lengths.  Given,  therefore,  a  solution  of  known  value,  that  is,  a 
standard  solution,  and  a  reaction  where  the  end  point  or  chemical  equi- 
librium can  be  made  visible  to  the  eye  by  any  means,  we  have  a  method 
which  can  be  used  to  measure  other  solutions  of  unknown  value.  When 
a  standard  solution  has  its  chemical  value  made  up  in  terms  of  the 
molecular  weight  of  the  substance  in  grams  per  liter,  it  is  called  a  molal 
solution.  It  is  more  convenient,  however,  to  make  up  such  solutions  on 
the  basis  of  the  hydrogen  equivalent  of  the  part  of  the  molecule  con- 
cerned, in  order  to  avoid  the  necessity  of  multiplying  or  dividing  by 
two  where  ions  of  different  valencies  interact.  Thus, 

2HC1  +  Na2C03  =  2NaCl  +  H2C03  would  call  for  two  molecular 
quantities  of  HC1  and  one  of  Na,CO3  or  one  of  HC1  and  y2  of  Na2C03. 
Again, 

HC1  +  Na2C03  =  NaCl  +  NaHC03  would  call  for  one  full  mole- 
cular quantity  of  HC1  and  y2  of  the  molecular  value  for  the  Na,C03. 
By  common  agreement  the  single  hydrogen  equivalent  has  been  adopted 
as  the  basis,  and  solutions  of  this  kind  are  called  normal  solutions. 
Hence,  a  normal  solution  of  the  first  substance,  HC1,  has  exactly  36.46 
grains  per  liter.  A  normal  solution  of  the  second  has  exactly  53.00 
grams  or  y2  of  the  molecular  weight,  106.0,  of  sodium  carbonate  per 
liter.  Where  solutions  of  less  strength  are  needed,  tenth  or  hundredth 

79 


10 


8o  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

normal  solutions  are  used,  expressed  thus: — N/10  or  N/]00.     Thus,  N/ 
sodium  carbonate  has  5.300  grams  of  the  pure  substance  per  liter  and 
each  c.c.  contains  .0053  gram  of  the  alkali. 

It  is  important  that  the  full  significance  and  value  of  the  processes 
involving  normal  solutions  be  well  understood  at  the  outset  of  the  work. 
The  preliminary  experiments  following  will  help  to  this  end. 

PRELIMINARY  EXPERIMENTS  * 

EXERCISE  I 

Standard  Sodium  Carbonate: — The  preparation  of  N/10  sodium  car- 
bonate solution  is  carried  out  as  follows : — 

Clean  and  dry  a  porcelain  crucible  or  small  porcelain  dish,  then 
ignite  it  lightly  and  cool  down  to  room  temperature,  putting  into  the 
desiccator  at  about  150°.  Weigh  accurately  and  add  about  six  grams, 
more  or  less,  of  pure,  dry  sodium  carbonate.  Eaise  to  a  red  heat,  short 
of  melting,  and  cool  in  a  desiccator.  Counterpoise  upon  the  balance  in 
such  a  manner  that  by  removing  with  a  clean  knife  blade  or  spatula  the 
excess  of  material,  there  shall  remain  in  the  crucible  exactly  5.300  grams 
of  the  carbonate.  Empty  the  carbonate  into  a  No.  3  beaker  and  add 
50  or  100  c.c.  of  distilled  water.  Einse  out  the  crucible  also  a  number 
of  times,  adding  the  washings  to  the  beaker.  After  solution  of  the 
carbonate  is  complete,  pour  the  contents  of  the  beaker  into  a  liter  meas- 
uring flask.  Einse  out  the  beaker  thoroughly,  transferring  the  washings 
to  the  flask  and  make  up  finally  to  the  mark.  The  temperature  of  the 
water  employed  for  making  up  to  volume  should  not  exceed  20° C. 
Stopper  and  mix  by  shaking  until  an  absolute  certainty  of  uniform 
distribution  of  the  solution  is  attained.  If  the  sodium  carbonate  is  pure 
and  the  proper  care  in  regard  to  transferring,  mixing,  temperature,  etc., 
has  been  observed,  we  should  now  have  a  strictly  N/10  solution.  To  test 
its  accuracy,  obtain  from  the  instructor  some  of  the  ready  prepared  N/10 
hydrochloric  acid  solution  and  proceed  as  follows. 

Measure  about  20  c.c.  of  the  sodium  carbonate  from  a  burette  into 
a  clean  beaker.  Add  about  20  c.c.  of  water  and  two  drops  of  methyl 
orange  solution.  Titrate  very  slowly  with  N/10  hydrochloric  acid 
from  a  burette.  Add  acid  drop  by  drop  until  the  yellow  turns  to  an 
orange  color.  More  acid  will  make  the  solution  pink,  but  this  is  too 
far — the  intermediate  orange  tint  denotes  neutrality.  More  accurate 
results  will  be  obtained  if  the  solutions  are  titrated  back  and  forth  until 
one  drop  of  either  solution  will  change  the  color  of  the  indicator.  Eepeat 
this  titration  three  times  and  average  the  results.  The  quantity  of  acid 
required  should  not  vary  from  the  solution  taken  by  more  than  0.1 
c.c.  If  there  is  a  greater  difference  than  this,  the  strength  of  the 
sodium  carbonate  solution  may  be  calculated  from  the  known  hydro- 


STANDARD  SOLUTIONS  81 

chloric  acid  solution.  This  correction  is  known  as  the  N/10  factor.  The 
factor  must  be  taken  into  consideration  whenever  the  sodium  carbonate 
solution  is  used.  The  exactly  N/10  solutions  are  much  to  be  preferred 
where  a  large  number  of  determinations  are  being  made.  What  applies 
to  the  sodium  carbonate  solution  is  equally  true  with  all  standard  solu- 
tions that  are  used.  From  the  N/10  sodium  carbonate  solution  make  a 
N/50  sodium  carbonate  solution. 

EXERCISE  II 

Standard  Sulphuric  Acid: — Prepare  a  N/10  solution  of  sulphuric 
acid  by  means  of  the  N/10  Na2C03  solution  as  follows : 

Measure  about  3%  c.c.  of  pure  concentrated  sulphuric  acid  into  a 
flask  containing  1050  c.c.  of  distilled  water.  Mix  thoroughly  and  fill  a 
50  c.c.  burette  with  the  solution.  Measure  20  c.c.  from  the  burette  into 
a  clean  beaker,  add  about  20  c.c.  of  water  and  2  drops  of  methyl  orange. 
Titrate  slowly  with  N/10  sodium  carbonate  solution  from  a  burette  until 
the  end  reaction  is  shown  by  the  first  change  of  color  from  pink  to 
orange.  Repeat  the  titration  as  before,  being  careful  to  note  the  correct 
color  for  the  end  point.  The  acid  solution  is  probably  too  strong.  If 
the  titration  with  N/10  sodium  carbonate  requires,  say,  21  c.c.  instead 
of  20  c.c.,  then  in  such  case  20  c.c.  of  acid  would  need  to  be  diluted  to 
21  c.c.  to  make  an  exact  balance  to  the  alkali  solution.  Similarly  200 
c.c.  would  need  to  be  diluted  to  210  c.c.  and  the  dilution  for  any  amount 
would  be  indicated  by  the  proportion 

20    :  21    ::  1000    :  x 

Hence,  in  the  above  example,  measure  an  exact  1000  c.c.  of  the  trial 
acid  and  add  50  c.c.  of  pure  water  to  it.  Test  the  accuracy  of  the  result- 
ing solution  with  N/10  sodium  carbonate  as  before. 

EXERCISE  III 

Determination  of  Sulphur: — (Consult  also  the  description  for  the 
determination  of  sulphur  under  Proximate  Analysis  of  Coal,  p.  103.) 

Measure  out  10  c.c.  of  the  x/10  sulphuric  acid  solution  and  make  up 
to  100  c.c.  Measure  carefully  10  c.c.  of  this  solution  into  a  100  c.c. 
cylinder  and  fill  two-thirds  full  of  water.  Add  5  drops  of  pure  concen- 
trated hydrchloric  acid,  make  up  to  the  100  mark,  pour  into  an  Erlen- 
meyer  flask  and  add  about  0.2  to  0.4  gram  of  special  Barium  Chloride 
powrder  (BaCl2  +  H2C204)  and  shake  thoroughly.  Warm  slightly  to 
prevent  the  crystallization  of  the  oxalate  salt.  Let  stand  for  15 — 20 
minutes  with  occasional  shaking.  Take  the  solution  to  the  photometer 
room. 


82  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

Light  the  gas,  adjusting  to  such  a  height  that  the  tip  of  the  flame 
just  appears  above  the  edge  of  the  metal  chimney.*  Turn  out  all  the 
lights  in  the  room.  Arrange  the  apparatus  so  that  looking  down  the 
graduated  tube  the  flame  is  seen  as  a  small  bright  point  in  the  center 
of  the  bottom  of  the  tube.  Now  run  in  the  solution,  with  barium  sul- 
phate in  suspension,  until  the  point  of  illumination  just  disappears  from 
sight.  Read  off  the  height  on  the  graduated  tube,  and  repeat  twice. 
If  the  column  is  less  than  60  or  more  than  160  m.m.  in  depth,  reject  the 
test  and  start  anew  using  double  or  half  the  quantity  of  solution  under 
test,  making  up  to  100  c.c.  in  each  case  as  before. 

On  page  107  will  be  found  a  curve  on  which  is  indicated  the  number 
of  grams  of  sulphur  per  100  c.c.  of  solution  corresponding  to  the  various 
heights.  Calculate  the  weight  of  sulphur  indicated  to  sulphuric  acid. 
Note  that  the  actual  amount  of  the  N/10  solution  taken  for  the  test  is  1  c.c. 

One  cubic  centimeter  of  N/10  sulphuric  acid  has  what  weight  of  acid 
present  ? 

How  much  sulphur? 

What  would  be  the  equivalent  amount  of  hydrochloric  acid?  So- 
dium Carbonate?  Calcium  carbonate? 

EXERCISE  IV 

Standard  Calcium  Chloride  and  Soap  Solutions: — Measure  from  a 
burette  into  a  clean  No.  2  beaker  40  c.c.  of  N/10  hydrochloric  acid.  What 
equivalent  does  it  contain  in  terms  of  sodium  carbonate  ?  What  equiva- 
lent in  terms  of  calcium  carbonate  ?  Weigh  carefully  0.210  gram  of 
pure  calcium  carbonate  powder  and  add  it  to  the  40  c.c.  of  N/10  hydro- 
chloric acid.  Cover  with  a  watch  glass  and  heat  for  a  few  minutes  till 
all  action  has  ceased.  Transfer  to  a  liter  flask.  Wash  out  the  beaker 
thoroughly  with  distilled  water,  transferring  the  washings  to  the  flask. 
Make  up  to  the  mark  and  mix  thoroughly  by  shaking.  Allow  the  con- 
tents to  stand  quietly  until  all  undissolved  material  has  settled  to  the 
bottom.  Siphon  off  half  or  more  of  the  clear  solution  into  a  suitable 
flask  and  label  "STANDARD  CALCIUM  CHLORIDE  SOLUTION".  Since  one 
c.c.  of  a  N/10  solution  is  equivalent  to  one  c.c.  of  any  other  N/10  solution, 
we  have  in  the  above  solution  40  c.c.  of  a  N/10  CaCl2  solution.  Although 
calcium  carbonate  is  not  soluble  in  water,  the  40  c.c.  of  N/10  calcium 
chloride  is  equivalent  to  the  amount  of  calcium  carbonate  in  40  c.c.  of  a 
theoretical  N/10  solution  of  calcium  carbonate.  Since  in  one  c.c.  of  a 

*A  tungsten  lamp  is  to  be  preferred  where  available.  It  should  be  3  to  4  volt, 
such  as  may  be  obtained  from  2  dry  cells  with  the  bulb  of  clear  glass  without  flaw. 


STANDARD  SOAP  SOLUTION  83 

N/10  solution  of  calcium  carbonate  there  are  .005  grams  of  calcium  car- 
bonate, in  the  40  c.c.  of  hydrochloric  acid  solution  or  the  liter  of  solution 
there  are  .2  grams  of  calcium  carbonate.  The  standard  calcium  chloride 
solution,  therefore,  has  a  value  of  200  parts  per  million  in  terms  of 
calcium  carbonate. 

The  standard  soap  solution  is  obtained  from  the  stock  shelf.  It  is 
prepared  by  dissolving  10  grams  of  castile  soap  in  100  c.c.  of  80  per 
cent  alcohol.  After  standing  for  several  days  it  is  further  diluted  with 
70  per  cent  alcohol  to  a  point  where  5  or  6  c.c.  of  it  as  measured  from 
a  burette  will  produce  a  permanent  lather  when  added  as  directed  below 
to  20  c.c.  of  the  standard  calcium  chloride  solution.  This  will  require 
usually  a  dilution  up  to  900  or  1000  c.c. 

Standardization  of  the  Soap  Solution: — Measure  20  c.c  of  the  stand- 
ard calcium  chloride  solution  into  a  250  c.c.  glass  stoppered  bottle  and 
add  30  c.c.  of  distilled  water.  Run  in  from  a  burette  the  standard  soap 
solution  0.4  or  0.5  c.c.  at  a  time,  shaking  the  bottle  vigorously  after  each 
addition.  Lay  the  bottle  on  its  side  after  each  shaking  and  note  if  the 
lather  remains.  The  end  point  is  taken  where  the  lather  remains  over 
the  entire  surface  of  the  water  for  five  minutes  after  shaking.  Make 
three  tests  of  the  standard  calcium  chloride  solution  as  above  prepared. 
Repeat  the  process,  using  10  c.c.  of  the  calcium  chloride  solution  and 
making  up  to  the  same  volume  (addition  of  40  c.c.  water)  as  before. 
By  thus  establishing  a  number  of  points  as  for  10,  15,  20  and  25  c.c., 
in  which  the  required  soap  solution  has  been  determined,  a  curve  for 
the  strength  of  the  soap  solution  is  developed  as  illustrated  in  the  chart, 
Fig.  14. 

The  hardness  of  a  water  is  due  to  any  mineral  constiuents  in  solu- 
tion other  than  compounds  of  sodium,  potassium,  ammonium,  etc.,  mem- 
bers of  the  first  or  soluble  group.  Upon  the  addition  of  soap  to  a  hard 
water  there  are  formed  insoluble  soaps  of  calcium,  magnesium  and  iron, 
which  are  precipitated  in  curdy  granules.  When  all  of  these  constituents 
are  precipitated  the  water  is  soft.  It  is  this  action  of  soap  which  per- 
mits of  its  use  in  a  standard  solution  for  measuring  the  total  hardness. 


84 


THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


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CUBIC  CENTIMETERS   SOAP  SOLUTION. 

Fig.    14.     Development   of   the   curve   for   a   standard   soap   solution,   with   the 
points  located  as  follows : — 

Point  No.  i,  using  10  c.c.  CaCl2  sol. 
Point  No.  2,  using  15  c.c.  CaCU  sol. 
Point  No.  3,  using  20  c.c.  CaCl2  sol. 
Point  No.  4,  using  25  c.c.  CaCl2  sol. 


WATER  ANALYSTS  85 

EXERCISE  V 

Determination  of  Calcium  Sulphate  in  Water: — Get  a  bottle  of 
unknown  "A"  for  analysis.  Add  25  c.c.  to  a  clean  beaker  with  a 
pipette,  then  run  in  10  c.c.  of  N/10  sodium  carbonate  solution.  Boil  for 
5  minutes  on  a  sand  bath,  then  filter  into  a  clean  beaker.  Wash  well 
with  hot  water,  saving  all  the  washings  until  the  liquid  leaving  the  fun- 
nel is  neutral  to  litmus  paper.  Now  add  2  drops  of  methyl  orange  to 
the  filtrate  and  washings  and  titrate  with  N/10  hydrochloric  acid. 

The  equation  representing  the  reaction  between  sodium  carbonate 
and  calcium  sulphate  is 

CaS04  +  Na2C03  =  CaC03  +  Na2S04. 

Since  the  titrated  sodium  carbonate  is  the  balance  of  the  10  c.c. 
remaining  unchanged  after  the  reaction  has  taken  place,  the  difference 
between  this  amount  and  the  10  c.c.  originally  added  represents  the 
amount  of  sodium  carbonate  taking  part  in  the  reaction,  and  from  this, 
remembering  always  the  equivalent  of  normal  solutions,  compute  the 
weight  of  calcium  sulphate  present.  Since  a  25  c.c.  sample  was  taken, 
how  many  grams  per  liter  did  the  solution  contain?  How  many  parts 
per  million?  How  many  grains  per  U.  S.  Gallon?* 

Calculate  also  the  lime,  in  grains  per  gallon,  equivalent  to  the 
calcium  sulphate  present.  Calculate  also  the  equivalent  of  calcium 
carbonate  in  grains  per  gallon  corresponding  to  the  sulphate  ion  present. 
From  the  amount  of  hydrochloric  acid  used,  calculate  the  sodium  chlo- 
ride (NaCl)  formed. 

2HC1  +  Na2C03  =  2NaCl  +  C02  +  H20. 

Perform  all  these  calculations  in  the  note  book  for  inspection  and 
reference. 

CHAPTER    VI 

BOILER  WATER  ANALYSIS 
EXERCISE  I 

Excess  or  Free  Carbon  Dioxide: — By  this  is  meant  the  carbon 
dioxide  held  in  solution  by  the  water.  It  is  not  scale  forming  material, 
but  in  water  treatment  it  behaves  as  so  much  temporary  hardness,  and 
the  amount  present  must  be  determined  in  order  to  gauge  correctly  the 
quantity  of  reagent  required  in  the  treatment.  The  "excess"  carbon 
dioxide  is  readily  taken  up  by  calcium  hydroxide,  Ca(OH)2,  forming 
*Milligrams  per  liter  or  parts  per  million  X  .0583  =  grains  per  U.  S.  gallon. 
See  p.  24. 


86  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

calcium  carbonate ;  or  by  sodium  carbonate,  forming  sodium  bicarbonate. 
So  long  as  there  is  present  free  carbon  dioxide,  it  acts  toward  phenolph- 
thalein  as  acid,  decolorizing  the  same.  The  first  excess  of  Na2C03  be- 
yond the  point  of  absorption  of  the  C02  is  denoted  by  a  pink  coloration 
of  the  indicator. 

Procedure. — With  the  graduated  cylinder  measure  200  c.c.  of  the 
water  into  a  No.  3  (350  c.c.)  beaker.  Add  a  few  drops  of  phenolphtha- 
lein  as  indicator  and  titrate  to  the  end  point  with  N/50  sodium  carbonate 
free  from  bicarbonate.  The  number  of  c.c.  used  times  5  represents  the 
equivalent  or  excess  of  C02  in  parts  per  million,  but  measured  in  terms 
of  calcium  carbonate. 

EXERCISE  II 

Total  Alkalinity  and  Temporary  Hardness: — Temporary  hardness 
is  due  to  the  calcium,  magnesium,  and  iron  held  in  solution  in  the  form 
of  bicarbonates.  They  are  readily  broken  down  by  dilute  acids  and, 
until  so  destroyed,  are  alkaline  towards  methyl  orange  indicator. 

Procedure. — Measure  200  c.c.  of  the  water  into  a  No.  3  beaker, 
add  a  few  drops  of  methyl  orange  and  titrate  with  N/10  sulphuric  acid. 
From  the  number  of  c.e.  used  can  be  calculated  the  equivalent  in  parts 
per  million  of  temporary  hardness  measured  in  terms  of  calcium  car- 
bonate. Note  that  to  calculate  the  value  in  c.c.  per  liter  we  would  need 
to  multiply  the  titration  by  five.  The  equivalent  value  for  N/10  sul- 
phuric acid  in  terms  of  calcium  carbonate  is  0.005  gram  per  c.c.  of 
solution.  Hence,  five  times  the  number  of  c.c.  per  liter  would  represent 
the  calcium  carbonate  in  milligrams  per  liter.  That  is,  25  times  the 
titration  number  represents  milligrams  per  liter  or  parts  per  million  of 
calcium  carbonate  equivalent. 

Note : — If  under  Exercise  V  below  sodium  carbonate  is  found  to  be 
present  as  negative  hardness,  the  temporary  hardness  is  equal  to  the 
total  alkalinity  minus  the  negative  hardness.  If  there  is  no  negative 
hardness  the  temporary  hardness  is  equal  to  the  total  alkalinity. 

EXERCISE  III 

Magnesia: — Use  the  solution  from  Exercise  II  above.  Cover  the 
beaker  with  a  watch  glass,  boil  for  fifteen  minutes,  add  50  c.c.  of  satu- 
rated lime  water  and  allow  to  stand  at  near  the  boiling  temperature  for 
about  fifteen  minutes.  Filter  into  a  250  c.c.  flask,  wash  with  boiled 
distilled  water  and  add  water  so  that  the  volume  at  room  temperature 
will  be  250  c.c.  Titrate  100  c.c.  with  N/10  sulphuric  acid,  using  the 
methyl  orange  indicator.  Make  at  the  same  time  the  same  determina- 
tion, using  pure  distilled  water  in  place  of  the  water  analyzed.  The 


WATER  ANALYSIS  87 

difference  between  the  two  titrations  is  the  amount  of  sulphuric  acid 
which  would  have  been  neutralized  by  the  calcium  hydroxide,  which 
has  precipitated  the  magnesium  from  the  water.  Since  the  amount 
titrated,  100  c.c.,  is  equal  to  2/5  of  the  250  c.c.,  it  must  also  be  equal  to 
2/5  of  the  original  200  c.c.  Then  the  difference  between  the  titrations 
multiplied  by  (5/2x5x5)  equals  the  equivalent  in  parts  per  million  of 
the  magnesia  in  the  water  measured  in  terms  of  calcium  carbonate. 

Note: — Because  of  the  solubility  of  magnesium  carbonate  in  the 
presence  of  alkali  bicarbonates,  it  is  necessary  to  precipitate  the  mag- 
nesium as  hydroxide.  In  wTater  treatment,  therefore,  the  magnesium 
bicarbonate  requires  double  the  amount  necessary  to  simply  bring  it  to 
the  carbonate  stage.  (See  p.  16,  Part  I). 

EXERCISE  IV 

Permanent  Hardness: — Boil  in  a  porcelain  dish  500  c.c.  of  the 
water  for  about  10  minutes  and  add*  25  c.c.  of  N/10  "soda  reagent" 
(equal  parts  of  sodium  hydroxide  and  sodium  carbonate)  and  boil  fur- 
ther to  about  y2  volume.  Filter,  wash  and  make  up  to  250  c.c.  Titrate 
100  c.c.  of  this  solution  with  N/10  sulphuric  acid,  using  methyl  orange 
as  an  indicator.  The  amount  of  original  water  used  is  then  200  c.c. 
since  the  100  c.c.  used  is  2/5  of  the  250  c.c.  and  consequently  2/5  of  the 
500  c.c.  The  difference  between  this  titration  and  the  amount  of  acid 
equivalent  to  25  c.c.  N/10  soda  reagent  multiplied  by  (5x5)  represents 
the  equivalent  of  permanent  hardness  in  parts  per  million  measured  in 
te,rms  of  calcium  carbonate.  Calculate  also  the  amount  in  parts  per 
million  of  the  sodium  sulphate  formed  by  the  reaction  and  refer  the 
result  for  use  under  exercise  number  IX. 

In  the  reaction,  as  with  "soda  reagent"  for  example 

CaSO4  +  Na2C03(25  c.c.)=  Na2S04  +  CaCO3  +  Na2C03(25  —  x)  c.c., 

it  is  seen  that  part  of  the  N/10  sodium  carbonate  has  changed  over  to 
sodium  sulphate.  The  extent  of  this  change  is  dependent,  of  course, 
upon  the  quantity  of  calcium  sulphate,  magnesium  sulphate,  etc.,  pres- 
ent in  the  water  and  the  measure  of  the  change  is  indicated  by  the  titra- 
tion of  the  nitrate.  It  is  to  be  noted  again  that  in  so  far  as  magnesium 
sulphate  may  be  present,  the  magnesium  carbonate  formed  is  soluble  to 
a  considerable  extent,  hence  the  more  insoluble  magnesium  hydroxide 
is  provided  for  by  the  use  of  the  "soda  reagent",  which  is  part  sodium 
hydroxide. 

Some  waters  will  give  a  titration  in  the  nitrate  which  is  greater  in 
amount  than  the  quantity  of  soda  reagent  added.  This  condition  is 
designated  as  negative  hardness. 


88  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

EXERCISE  V 

Negative  Hardness: — Throughout  this  region  a  very  large  percent- 
age, especially  of  the  deep  wells,  yield  waters  of  Class  I,  as  described  on 
page  11.  Such  waters  have  no  sulphates  of  calcium  or  magnesium  pres- 
ent. They  have,  however,  some  free  sodium  bicarbonate  instead,  which 
indicates  that  some  such  reaction  as  indicated  in  Exercise  IV  above  has 
taken  place  while  the  water  was  percolating  through  the  ground.  The 
treatment,  therefore,  prescribed  above  would  result  simply  in  the  addi- 
tion of  more  alkali.  Hence,  the  excess  of  acid  required  over  the  10  c.c. 
of  alkali  added  would  be  a  measure  of  the  free  sodium  carbonate  or 
"negative  hardness"  present.  Multiplying  by  (5x5.3)  would  give  the 
weight  in  milligrams  per  liter  of  Na2C03.  Calculate  the  negative  hard- 
ness in  terms  of  calcium  carbonate  in  order  to  obtain  the  temporary  hard- 
ness. Determine  the  amount  of  negative  hardness  in  the  laboratory  tap 
water. 

EXERCISE  VI 

Total  Hardness: — The  total  hardness  of  a  water  may  be  derived 
(a)  from  the  data  which  has  resulted  from  experiments  II  and  IV  above, 
and  (b)  from  the  soap  test.  It  is  well  to  use  both  sources  of  information 
as  a  check. 

(a)  Under  experiment  II  there  will  be  measured  the  amount  of 
temporary   or  bicarbonate   hardness,   that  is,   the   amount  of   calcium, 
magnesium  and  iron  present  as  bicarbonates,  but  measured  all  together 
in  terms  of  calcium  carbonate  by  the  titration  with  N/10  hydrochloric 
acid  or  sulphuric  acid. 

Under  experiment  IV  there  will  be  indicated  the  amount  of  sul- 
phate or  chloride  hardness;  that  is,  the  amount  of  calcium,  magnesium 
or  iron  which  may  be  present  in  the  form  of  the  sulphates  or  chlorides 
of  these  elements,  but  measured  again  in  the  equivalent  of  calcium 
carbonate.  Be  sure  that  experiment  No.  V  has  been  taken  into  this 
account,  for,  if  free  sodium  bicarbonate  is  present,  there  will  be  110 
permanent  but  only  temporary  hardness  to  enter  into  the  total  hard- 
ness. The  sum  of  the  temporary  hardness  and  permanent  hardness,  (if 
any),  given  in  terms  of  calcium  carbonate,  represents  the  total  hardness. 

(b)  Make   a   determination   of  total   hardness   by   means   of   the 
standard  soap  solution  as  follows : — 

Measure  50  c.c.  of  the  water  into  a  No.  3  beaker,  add  a  few  drops 
of  methyl  orange  and  titrate  with  N/10  sulphuric  acid  to  the  end  point. 
Transfer  the  water  thus  neutralized  to  the  shaking  bottle  used  for  the 
soap  test  and  run  in  from  a  burette,  the  standard  soap  solution,  a  few 
tenths  of  a  cubic  centimeter  at  a  time,  shaking  vigorously  after  each 
addition.  The  end  point  is  taken  in  the  same  manner  by  noting  where, 


USE  OF  SOAP  SOLUTION 


89 


upon  laying  the  bottle  on  its  side  after  shaking,  the  lather  remains  for 
five  minutes.  With  waters  containing  magnesium  salts  care  must  be 
taken  to  avoid  mistaking  the  salts  of  magnesium  end  point.  After  the 
titration  is  apparently  finished  read  the  burette  and  add  5  c.c.  of  soap 
solution.  If  the  end  point  was  due  to  magnesium  the  lather  disappears. 
Continue  the  addition  of  soap  solution  until  the  true  end  point  is  reached. 
Upon  the  page  of  dimension  paper  herewith,  locate  a  curve  which 
represents  the  strength  of  the  soap  solution  used  and  from  this  read  the 


/£/ 

So 

— 

o 

Q 

6  no 

0 

2 

R   7* 

| 

M 

§ 

P3    60 

ft  , 

EH 

2] 

4o 

So 

u 

!l 

( 

t 

*" 

^ 

> 

r 

^ 

5 

CUBIC  CENTIMETERS   SOAP  SOLUTION 

FIG.  15.     PLOTTING  A  CURVE  FOR  STANDARD  SOAP  SOLUTION 

Showing  the  value  in  parts  per  million  of  CaCOs. 


90  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

amount  of  parts  per  million  in  terms  of  calcium  carbonate.  How  does 
the  amount  compare  with  the  total  hardness  as  derived  under  (a)  above? 

EXERCISE  VII 

Determination  of  Total  Sulphates. — Into  a  100  c.c.  cylinder  meas- 
ure 50  c.c.  of  water  and  add  2  or  3  drops  of  concentrated  hydrochloric 
acid.  Make  up  to  exactly  100  c.c.  in  the  graduated  cylinder.  Pour 
into  an  Erlenmeyer  flask  of  about  200  c.c.  capacity  and  add  Special 
Barium  Chloride  as  in  Exercise  II  of  Section  II  for  the  determina- 
tion of  sulphuric  acid.  Warm  slightly.  After  standing  15-20  minutes, 
read  in  the  photometer  as  directed  in  Preliminary  Exercise  III  of  Chap- 
ter II.  Refer  to  the  chart  on  page  107  for  the  weight  of  sulphur  indi- 
cated by  the  photometer  reading.  Calculate  to  sulphuric  acid  thus 

32  :  142  : :  wt.  of  S.  :  Na2S04 
EXERCISE  VIII 

Determination  of  Total  Chlorides: — Measure  accurately  50  c.c.  of 
water  by  means  of  a  50  c.c.  pipette  into  a  porcelain  dish.  Add  about  1 
c.c.  of  potassium  chromate  solution  and  titrate  with  N/100  silver  nitrate 
solution,  until  the  yellow  color  gives  place  to  the  first  permanent  trace 
of  reddish  brown,  do  not  wait  for  a  red  tint  to  appear.  Fill  another 
porcelain  dish  with  50  c.c.  of  distilled  water  and  add  1  c.c.  of  the  indi- 
cator. Use  this  as  a  standard  of  comparison.  The  first  tinge  of  brown- 
ish red  that  can  be  distinguished  in  the  titrated  solution  is  to  be  taken 
as  the  end  point. 

The  reactions  involved  are — 

2AgN03  +  K2Cr04  —  2KN03  +  Ag2Cr04. 

The  silver  chromate  is  a  red  precipitate,  but  as  long  as  there  is  any 
soluble  chloride  in  solution,  this  breaks  up  the  chromate  as  follows — 

Ag2Cr04  +  CaCl2  =  2AgCl  +  CaCrO4. 

Thus,  the  first  tinge  of  pink  shows  that  the  chlorine  of  the  chloride  has 
all  been  precipitated.  From  the  volume  of  silver  nitrate  used  to  this 
point,  calculate  the  weight  of  chlorine  in  the  50  c.c.  taken  thus 

Vol.  N/ioo  AgN03  X  .0003545  =  wt.CL  in  50  c.c. 

and  0.0005845  X  the  vol.  N/100  AgN03  =  wt.  NaCl  in  50  c.c.  of  the  water. 
Multiplying  further  by  20  will  give  the  weight  per  liter.  From  this  is 
indicated,  by  referring  to  milligrams,  the  milligrams  per  liter  or  parts 
per  million. 


ALKALINITY  91 

EXERCISE  IX 

Total  Alkalies: — The  total  alkalies  are  considered  as  being  made 
up  of  all  the  sulphate  not  combined  as  permanent  hardness  and  all  of 
the  chlorides.  It  is  true  that  small  amounts  of  other  alkali  salts,  as 
sodium  nitrate,  are  present  and  occasionally  some  of  the  chloride  is 
present  as  magnesium  or  calcium  chloride;  but,  for  the  scope  of  this 
work  and  for  ordinary  technical  requirements,  it  is  quite  sufficient  to 
consider  the  total  alkalies  as  being  constituted  as  above  indicated. 

Procedure : — From  the  total  sulphate  as  determined  under  No.  VII 
and  calculated  to  sodium  sulphate,  subtract  the  sulphate  hardness  as 
found  under  No.  IV  and  which  was  there  calculated  also  to  the  equiva- 
lent of  sodium  sulphate  for  this  purpose.  The  remainder  is  the  amount 
of  alkalies  existing  in  the  water  in  the  form  of  sodium  sulphate.  To 
the  above  should  be  added  the  total  chloride  results  under  No.  VIII, 
calculated  to  sodium  chloride. 

If  free  sodium  carbonate  or  negative  hardness  was  developed  under 
No.  V  then  this  also  in  the  form  of  equivalent  sodium  carbonate  should 
be  added  as  a  third  constituent  of  the  alkalies. 

The  sum  of  these  various  constituents,  referred  in  each  instance  to 
parts  per  million,  is  to  be  taken  as  the  total  alkalies  in  parts  per  million. 
Calculate  this  sum  also  to  grains  per  U.  S.  Gallon. 

EXERCISE  X 

Examination  of  a  Treated  Water: — 1.  If  the  water  has  been  under 
treated,  it  is  possible  to  determine  as  with  an  untreated  water  the 
amounts  of  lime  and  soda  still  needed  to  soften  water. 

2.  In  case  excess  of  soda  ash  has  been  added,  the  permanent  hard- 
ness will  be  negative;  and,  if  the  water  has  no  sodium  carbonate  present 
originally,  1.06  times  the  negative  hardness  expressed  as  parts  per  mil- 
lion of  calcium  carbonate  represent  the  excess  of  sodium  carbonate  which 
has  been  added  to  the  water. 

3.  In  most  cases,  however,  a  treated  water  is  alkaline  to  phenolph- 
thalein,  in  which  case  200  c.c.  is  titrated  with  N/10  sulphuric  acid,  to  the 
end  point  with  phenolphthalein  and  then  on  to  the  end  point  with  methyl 
orange. 

If  the  amount  of  acid  needed  to  give  the  end  point  with  the  phe- 
nolphthalein is  more  than  half  that  which  is  needed  to  give  the  end 
point  with  methyl  orange,  an  excess  of  lime  is  present.  If  the  difference 
between  the  two  qauntities  be  subtracted  from  the  number  of  c.c.  for 
the  phenolphthalein  end  point,  the  result  shows  the  calcium  carbonate 
equivalent  in  parts  per  million  of  the  excess  of  pure  lime,  CaO.  This 
equivalent  multiplied  by  56  gives  the  parts  per  million  of  CaO  and  this 
result  multiplied  by  .0583  gives  the  amount  in  pounds  per  1000  gallons. 


92  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

EXERCISE  XI 

Summary  of  results  and  calculations: — The  character  of  a  water  is 
shown  by  assembling  in  tabular  form  the  various  ingredients  grouped 
in  a  manner  to  indicate  the  total  scale-forming  and  the  total  foaming 
ingredients,  as  called  for  in  the  accompanying  outline.  This  summary 
calls  for  the  various  results  in  grains  per  gallon,  and  the  order  and 
grouping  is  that  of  the  exercises  I  to  X. 

The  calculations  for  the  requisite  amount  of  reagents  to  remove  the 
scaling  ingredients  involve  simply  the  calculation  from  the  determined 
equivalent  of  calcium  carbonate  over  to  the  proper  reacting  substance, 
thus — 

Since  one  equivalent  of  excess  C02,  one  equivalent  of  temporary 
hardness  or  one  equivalent  of  magnesium  requires  one  equivalent  of 
calcium  oxide  for  its  removal  from  the  water,  0.56  times  the  sum  of  the 
calcium  carbonate  equivalent  of  excess  carbon  dioxide,  temporary  hard- 
ness, and  magnesium  represents  the  number  of  parts  per  million  of  pure 
lime  CaO,  necessary  to  remove  these  difficulties. 

1.06  times  the  calcium  carbonate  equivalent  of  the  permanent  hard- 
ness is  the  number  of  parts  per  million  of  sodium  carbonate,  Na2C03, 
necessary  to  remove  the  permanent  hardness.  0.0583  times  the  quanti- 
ties in  parts  per  million  gives  the  pounds  per  thousand  gallons  needed. 
The  results  above  are  for  pure  lime  and  sodium  carbonate.  Commercial 
lime  and  soda  ash  must  be  analyzed  to  determine  the  amounts  of  pure 
lime  and  sodium  carbonate  which  they  contain. 

Note: — As  an  aid  to  calculations  and  a  correct  designation  of  the  kind  of 
alkalinity  present  the  following  table  will  be  found  helpful: 

Letting  P  t  stand  for  the  titration  when  using  phenolphthalein  and  M  o  for 
the  titration  when  using  methyl-orange,  then, — 

When  P  t  =        M  o there  are  present  hydroxides  only. 

"      P  t  <        M  o  >  y2  M  o  "     "          "      hydroxides  and  normal  carbonates. 
"      P  t  =  y2  M  o  "        "          "      normal  carbonates  only. 

"      P  t  <  l/2  M  o  "        "          "      normal  carbonates  and  acid  carbonates. 

"      P  t  =        Mo  "        "          "      acid  carbonates  only. 


UNIVERSITY    OF    ILLINOIS 
DEPARTMENT  OF  APPLIED  CHEMISTRY 
Analysis  of  Boiler  Water  from 


No 


Sample  Taken 191. 


Free  C02 
as  CaCOs  Equiv 

Total  Alkalinity  as 
CaCOs  Equiv 

Temporary  hardness  as 
CaCOs  Elquiv 

Negative  hardness  as 
CaCOs  Equiv 

Magnesium  as 
CaCOs  Equiv 

Permanent  hardness  as 
CaCOs  Equiv 


Total  scale  forming 
material 


Alkalies  as  Na2S04 
Alkalies  as  NaCl 
Alkalies  as  Na2CO3 


Parts  per     j  Grains  per 
million  gallon 


Requiring  for  treatment 
of  1000  gallons 


Gallons  of 
saturated 
CaO  Sol. 


Ibs.  of  99.0 
%  Soda  Ash 


Remarks 


By 


93 


CHAPTER   VII 
THE  PROXIMATE  ANALYSIS  OF  COAL. 

Introduction: — The  procedure  as  here  outlined  for  the  proximate 
analysis  of  coal  follows  substantially  the  final  report  on  methods  of 
analysis  as  adopted  by  the  joint  committee  of  the  American  Chemical 
Society  and  the  American  Society  for  Testing  Materials.  The  prelimi- 
nary report  of  this  committee  published  in  the  Journal  of  Industrial 
and  Engineering  Chemistry  for  June  13,  Vol.  5,  p.  17,  contains  much 
detail  of  value  relating  to  sources  of  error  and  general  conditions  to  be 
observed  in  the  procuring  of  accurate  results.  The  final  report  is  in  a 
much  more  condensed  form  and  is  intended  as  a  guide  for  every-day 
procedure  in  connection  with  coal  contracts,  and  inspection.  This  was 
printed  as  the  report  of  Committee  E-4  and  presented  at  the  annual 
meeting  of  the  American  Society  for  Testing  Materials,  June,  1915. 

EXERCISE  I. 

Moisture  Loss  on  Air  Drying: — The  sample  as  prepared  for  the 
laboratory  should  be  four  or  five  pounds  in  amount  and  transmitted  in 
an  air  tight  container.  If  the  directions  for  sampling  with  regard  to, 
the  fineness  of  division  have  been  observed  the  laboratory  sample  will 
be  approximately  4-mesh  or  %  inch  in  the  diameter  of  the  largest 
particles. 

Spread  the  sample  on  a  tared  pan  about  18"  x  18"  x  1%"  in  depth. 
Weigh  and  air  dry  at  room  temperature  or  in  a  special  drying  oven 
through  which  a  current  of  air  is  circulated  and  in  which  the  tempera- 
ture is  maintained  at  15°  to  25°  Fah.  above  that  of  the  room.  Weigh 
again  after  twelve  hours.  The  moisture  content  should  now  be  in 
approximate  equilibrium  with  the  moisture  of  the  air.  This  will  mean 
a  moisture  factor  of  from  3  to  5  per  cent.  It  may  be  indicated  by  the 
fact  that  a  continuation  of  the  drying  process  will  not  show  a  loss  of 
more  than  0.1  per  cent  per  hour.  Note  the  loss  of  moisture  011  air- 
drying  and  calculate  to  per  cent  of  the  entire  sample. 

Working  Sample: — Pass  the  air  died  sample  entire  at  once  after 
final  weighing,  through  a  grinder  of  the  coffee  mill  type  set  to  grind 
to  about  20  mesh.  Immediately  after  passing  through  the  grinder, 
spread  out  on  a  tray  and  with  a  spoon  take  from  various  parts  a  60 
gram  sample  and  place  directly  in  a  rubber-stoppered  bottle  and  label 
"For  Total  Moisture". 

Thoroughly  mix  the  main  portion  of  the  sample,  reduce  by  means 
of  a  riffle  to  about  60  grams.  Pulverize  to  60  mesh  on  the  bucking 
board,  passing  all  of  the  material  through  the  sieve.  Transfer  to  a  four- 
ounce  rubber  stoppered  bottle  and  label  "Laboratory  Sample  for  Coal 
Analysis". 

94 


MOISTURE  AND  ASH  95 

EXERCISE  II. 

Total  Moisture:  —  In  a  dry  glass  capsule  with  ground  glass  cover 
weigh  out  5  grams  of  the  20-mesh  sample  labeled  "For  Total  Moisture". 
Heat  with  the  cover  off  for  iy2  hours  in  an  oven  maintained  at  104°  to 
110°  C.  Cool  in  a  desiccator  over  concentrated  sulphuric  acid,  sp,  gr. 
184.  "Weigh.  Calculate  the  moisture  thus  found  to  the  percentage  it 
would  be  of  the  original  coal  before  air  drying  and  add  to  the  air-drying 
loss,  thus,  —  subtract  the  percentage  loss  on  air-drying  from  100  and 
multiply  by  the  oven  drying  loss  to  find  the  percentage  to  be  added,  or 
as  a  formula:  — 

\        s       ! 

-f 


J.UU 

in  which  (a)  is  the  moisture  loss  on  air-drying  and  (a1)  is  the  loss  on 
drying  the  air-dry  sample  at  104°—  110°  C. 

Moisture  in  the  Laboratory  Sample:  —  Determine  the  moisture  on 
the  60-mesh  laboratory  sample,  by  weighing  out  1  gram  in  a  glass  cap- 
sule as  in  Exercise  II  and  drying  with  the  cover  off  at  104°  —  110°  C. 
for  one  hour.  Replace  the  cover,  cool  in  the  desiccator  and  weigh.  The 
loss  of  weight  is  the  amount  of  water  in  the  sample.  Save  for  ash 
determination. 

EXERCISE  III. 

Ash:  —  Transfer  the  1  gram  of  coal  remaining  in  the  glass  capsule 
from  the  moisture  determination  to  a  porcelain  crucible.  Place  on  a 
triangle  2  or  3  inches  above  the  tip  of  a  flame  which  has  been  turned 
down  to  about  2  inches  in  height.  It  can  be  left  in  this  condition  with- 
out attention  for  15  or  20  minutes,  when  most  of  the  carbonaceous  mat- 
ter will  have  been  burned  off.  Lower  the  crucible  to  within  14  or  % 
inch  of  the  flame  and  leave  without  attention  for  an  equal  length  of 
time.  Occasional  stirring  with  a  platinum  wire  will  facilitate  the  oxida- 
tion. Finally  place  the  crucible  on  the  triangle  in  an  inclined  position 
so  as  to  facilitate  the  circulation  of  air  currents  over  the  ash;  apply 
the  blast  flame  to  the  bottom  of  the  crucible  for  5  to  10  minutes  or  until 
the  ash  does  not  lose  in  weight  upon  further  blasting.  Cool  in  the 
desiccator  and  weigh.  Subtract  the  weight  of  the  crucible  and  compute 
the  weight  of  the  ash  to  percentage  of  air  dry  coal. 

EXERCISE  IV. 

Volatile  Matter,  Official  Method:  —  The  standard  method  for  deter- 
mining the  volatile  matter  in  coal  as  indicated  by  the  joint  committee 
on  coal  analysis  in  the  Journal  of  Industrial  and  Engineering  Chemis- 
try, June,  1913,  prescribes  the  use  of  a  platinum  crucible  with  capsule 


96  THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

cover  fitting  inside  of  the  crucible; — that  is,  telescoping  %  to  1/4  of  an 
inch,  instead  of  an  ordinary  cover  resting  on  the  upper  edge.  The 
crucible  with  1  gram  of  coal  is  placed  in  a  muffle  maintained  at  950°  C. 
(±20°  C.)  A  vertical  electrically  heated  muffle  is  easy  of  construc- 
tion and  greatly  to  be  preferred  for  this  work.  On  account  of  the 
variation  in  pressure  and  heating  value  of  city  gas  it  is1  practically 
impossible  to  obtain  consistent  results  with  the  Bunsen  or  Meker  burn- 
ers. A  muffle  heated  by  gas  and  maintained  at  the  proper  temperature 
is  much  to  be  preferred  to  heating  by  the  direct  flame. 

On  account  of  the  expense  of  platinum  the  use  of  a  porcelain,  cru- 
cible is  necessary  in  class  work  as  indicated  below.  It  is  to  be  noted  that 
any  method  which  retards  the  transmission  of  heat  to  the  coal  will  result 
in  a  lower  indicated  amount  for  volatile  matter,  and  a  correspondingly 
higher  percentage  for  fixed  carbon.  To  overcome  this  discrepancy, 
therefore,  the  porcelain  crucible  is  put  directly  into  a  highly  heated 
chamber  and  the  heat  applied  from  the  first  at  or  above  the  prescribed 
temperature.  In  this  manner  the  results  should  check  the  official  method 
within  0.5  per  cent.  The  volatile  matter  values  will  be  found  consistently 
lower  than  percentages  obtained  by  the  official  method  by  about  that 
amount. 

Porcelain  Crucible  Method: — Select  a  porcelain  crucible  with  well 
fitting  cover,  ignite,  with  cover,  in  the  flame  of  a  Bunsen  burner  to  a 
dull  red  heat,  cool  in  the  desiccator  and  weigh.  Place  a  nichrome  triangle 
over  a  blast  lamp  and  over  the  triangle  place  an  inverted  20  gram  assay 
crucible  with  the  bottom  ground  off,  exposing  a  hole  approximately  one 
inch  in  diameter.  "When  this  apparatus  is  heated  to  as  high  a  tempera- 
ture as  possible,  remove  the  inverted  crucible,  put  in  place  the  porcelain 
crucible  with  cover  on  containing  one  gram  of  air-dry  coal.  Continue 
the  heating  for  seven  minutes  and  at  the  end  of  this  period  turn  off  the 
flame  and  remove  the  assay  crucible  but  do  not  disturb  the  cover  of  the 
porcelain  crucible  until  the  same  has  been  reduced  below  a  red  heat. 
Transfer  to  a  disiccator,  cool  and  weigh  with  the  cover.  The  loss  in 
weight  minus  the  moisture  present  is  the  weight  of  volatile  matter. 

EXERCISE  V. 

Fixed  Carbon: — The  sum  of  the  percentages  for  moisture,  (on  the 
air  dry  or  working  sample)  ash,  and  volatile  matter,  subtracted  from 
100,  will  leave  as  a  remainder  the  percent  of  fixed  carbon  in  the  air  dry 
coal. 

Calculations: — Calculate  each  value  for  the  air  dry  sample  to  per- 
centages of  dry  (moisture  free)  coal  by  dividing  each  by  1.00 — the 
weight  found  for  that  constituent. 

Calculate  to  the  "as  received"  basis  by  multiplying  each  factor  as 
derived  for  the  dry  coal  by  1 — the  total  moisture  factor. 


OPERATION  OF  THE  PEROXIDE  CALORIMETER  97 

EXERCISE  VI. 

Calorific  Value: — If  the  amount  of  moisture  in  the  air-dried  coal 
is  less  than  two  per  cent,  no  drying  in  the  oven  is  necessary  for  the 
determination  of  calorific  value.  One-half  gram  of  air-dried  coal  is  used 
and  the  detailed  directions  should  be  followed  as  given  below. 

General  Arrangement: — The  Calorimeter  should  be  placed  on  a 
good,  firm  desk  in  a  room  where  the  fluctuations  of  temperature  may  be 
avoided.  The  general  arrangement  of  parts  is  shown  in  Fig.  16.  How- 


Fig.  16 
Calorimeter  Using  Sodium  Peroxide 

ever,  it  is  better  to  remove  the  can  5C  from  the  instrument  for  filling 
with  water.  The  outside  of  the  can  should  be  dry,  and  no  water  should 
be  allowed  to  spill  over  into  the  air  spaces  of  the  insulating  vessels. 

Exactly  two  liters  of  water  (preferably  distilled)  are  used,  and  it 
should  have  a  temperature  of  2  or  3  degrees  F.  below  that  of  the  room. 


THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


The  thermometer  46 C  should  extend  a  little  over  half  way  to  the  bottom 
of  the  can.  The  pulley  37C  is  connected  by  a  light,  flexible  cord  with  a 
small  electric  or  water  motor.  Stirring  is  effected  by  the  spring  clips 
with  turbine  wings  20AC  placed  on  the  bell  body.  The  pulley  37C 
must  be  made  to  revolve  at  a  rather  brisk  rate.  About  150  revolutions 
per  minute,  uniformly  maintained,  will  insure  a  complete  equalization 
of  temperature  throughout  the  water.  The  pulley  should  turn  to  the 
right  or  as  the  hands  of  a  watch. 

The  Chemical:  Sodium  Peroxide  Na202: — It  is  absolutely  necessary 
that  the  chemical  employed  (sodium  peroxide)  be  kept  free  from  con- 
tamination. It  has  special  avidity  for  moisture,  and  the  glass  jar  with 
lever  fastener,  as  shown  in  Fig.  17,  has  been  found  best  adapted  as  a  con- 
tainer for  this  material.  The  sodium  peroxide  is  furnished  in  small 
sealed  tins,  and  the  entire  contents  of  a  can,  upon  opening,  should  be 
transferred  completely  to  the  jar.  The  half-pound  tins  will  usually  be 
found  the  most  convenient  size  to  use.  In  any  event,  the  glass  jar  should 
be  of  sufficient  size  to  permit  of  the  complete  emptying  of  the  container. 


Fig.  17 
Container  for  Sodium  Peroxide. 

Commercial  sodium  peroxide  or  material  that  has  been  much  exposed 
to  the  air  so  that  any  considerable  amount  of  moisture  has  been  absorbed, 
will  give  variable  and  uncertain  results. 

The  Accelerator:  Potassium  Chlorate f  KCIOS: — In  order  to  secure 
a  combustion  that  shall  be  uniformly  complete,  it  has  been  found  desir- 
able to  use  an  accelerator  for  the  purpose  of  increasing  or  intensifying 
the  oxidizing  effect  of  the  sodium  peroxide.  While  numerous  chemicals 


THE  PEROXIDE  BOMB  AND  CHARGE 


99 


and  mixtures  have  been  tried,  a  very  extended  experience  has  made  it 
evident  that  potassium  chlorate  is  best  adapted  for  this  purpose.  The 
amount  needed  for  each  charge  is  weighed  out  in  the  same  manner  as 
for  coal.  One  gram  is  the  weight  taken  for  fuel  of  all  types. 

Making  Up  the  Charge: — See  that  the 
floating  bottom  4AC  is  in  place  at  the  lower 
end  of  the  bell  body  as  shown  in  Fig.  18.  The 
inner  surfaces  should  be  dry  so  that  the 
fusion  cup,  when  put  in  place,  will  be  sur- 
rounded by  an  air  space  with  no  film  of  wa- 
ter present.  The  fusion  cup  also  should  be 
thoroughly  dry  inside  before  adding  the 
charge.  It  is  well  to  dry  it  over  a  radiator 
or  hot  plate,  though  it  should,  of  course,  be 
cooled  for  filling.  Add  to  the  fusion  cup,  not 
assembled,  one  full  measure  of  sodium  per- 
oxide. In  filling  the  measure  with  peroxide, 
it  should  be  tapped  against  the  side  of  the 
glass  jar  to  insure  against  the  formation  of 
air  pockets  which  might  prevent  the  complete 
filling  of  the  measure.  The  same  precaution 
also  as  to  the  dryness  of  the  measure  should 
be  observed  as  for  the  fusion  cup.  It  should 
be  rinsed  thoroughly  with  tap  water  after 
each  using  and  dried  by  heating  over  a  radia- 
tor or  hot  plate.  Add  one  gram  of  accelera- 
tor immediately  after  adding  the  sodium  per- 
oxide. If  the  accelerator  is  lumpy,  it  is  well 
to  rub  it  smooth  in  a  glass  or  agate  mortar 
before  weighing.  Close  with  the  false  top 
Fig.  18  36C,  Fig  19,  and  shake  thoroughly  until  the 

Peroxide  Bomb.  ingredients  are  evenly  mixed.     Add  now  % 

gram  of  oven-dry  coal.  Replace  the  false  top  and  shake  again.  When 
the  mixing  is  complete,  tap  the  holder  lightly  on  the  desk  to  shake  all 
of  the  material  from  the  upper  part  of  the  container,  remove  the  false 
cap  and  put  in  its  place  the  regular  cap  with  stem  and  ignition  wire 
SAC.  To  attach  the  ignition  wire,  take  a  single  length  of  fuse  wire  7cm. 
long  from  the  card ;  pass  one  end  through  the  eyelet  of  one  of  the  term- 
inals, 24AC,  so  it  will  extend  beyond  the  eyelet,  sayi/i".  Wrap  the 
free  wire  around  the  terminal  at  the  narrow  portion  formed  by  the 
notch,  giving  it  three  turns,  binding  in  the  free  end  and  bending  the  wire 
finally  downward  in  line  with  the  terminal.  Repeat  the  same  process 
with  the  other  end  of  the  wire  in  the  other  terminal  23 AC.  Do  not 


ioo         THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

have  the  fuse  loop  too  long.  It  is  better  not  to  extend  too  far  into  the 
charge.  It  will  be  noticed  that  the  charge  fills  the  crucible  at  least  two- 
thirds  full ;  hence,  %"  extension  of  the  fuse  wire  below  the  central  term- 
inal will  be  ample. 

See  that  the  rubber  gasket  27AC  is  in  good  shape  and  that  the  stem 
cap  seats  itself  properly.  It  is  to  be  noted  that  the  gasket  seals  both 
the  upper  edge  of  the  crucible  and  also  the  upper  edge  of  the  bell  body. 
Marring  the  edges  or  rims  of  any  of  these  parts,  therefore,  must  be 
carefully  avoided.  Screw  down  the  cap  5AC  firmly  in  place  by  use  of 
the  two  wrenches ;  put  on  the  spring  clips  with  the  stirring  vanes  down- 
ward, leaving  the  small  holes  near  the  lower  edge  of  the  bell  body 
uncovered  and  assemble,  as  shown  in  Fig.  16.  In  assembling,  bring 
the  can  to  its  proper  place  and  add  2  liters  of  distilled  water  having  a 
temperature  2°  or  3°  F.  below  that  of  the  room.  In  placing  the  bomb 
in  the  water  hold  it  in  an  inclined  position  in  such  a  manner  that  the 
lower  edge  of  the  bell-body  will  enter  the  water  at  an  angle  and  thus 
avoid  entrapping  an  air  pocket  under  the  bottom. 

Ignition: — The  current  required  for  igniting  the  charge  should  be 
from  two  to  four  amperes,  and  is  readily  obtained  by  placing  in  parallel 
five  16-candle  power  lamps  in  an  ordinary  lighting  circuit  of  110  volts. 
It  is  well  to  have  the  fifth  lamp  of  32-candle  power.  Ely  this  means  a 
suitable  current  is  readily  obtained. 

Make  a  number  of  preliminary  tests  by  fastening  a  loop  to  the  term- 
inals and  passing  the  current  without  assembling  the  parts.  In  this 
way  the  behavior  of  the  fuse  can  be  observed.  Make  a  trial  with  three 
or  four  lamps  in  the  circuit.  If  the  wire  does  not  come  very  quickly 
to  incandescence,  increase  the  resistance  until  it  melts  with  one  or  two 
seconds'  delay  upon  closing  the  circuit. 

Temperature  Readings: — The  thermometer  is  inserted  so  that  the 
lower  end  of  the  bulb  will  be  about  midway  toward  the  bottom  of  the 
can.  The  pulley  should  be  allowed  to  revolve  a  few  minutes  before  read- 
ing the  thermometer,  in  order  to  equalize  the  temperature  throughout  the 
apparatus.  Take  readings  one  minute  apart  for  two  or  three  intervals 
before  igniting  the  charge,  and  continue  the  same  for  nine  or  ten  minutes 
subsequent  to  ignition.  The  first  three  or  four  readings  after  ignition 
are  roughtly  taken,  but  after  the  fourth  or  fifth  minute  the  temperature 
should  be  nearly  equalized,  and  the  readings  must  be  carefully  taken  in 
order  to  ascertain  the  exact  maximum  and  to  furnish  the  necessary  data 
for  making  a  correction  for  radiation.  If  the  temperature  of  the  water 
before  ignition  is  one  or  two  degrees  below  that  of  the  room,  the  temper- 
ature at  the  end  of  the  first  minute  after  ignition  will  be  something  above 
that  of  the  room,  and  radiation  for  that  period  may  be  considered  as 
self-correcting.  Ordinarily,  the  rise  in  temperature  will  continue  for 


CALCULATIONS  AND  CORRECTION  FACTORS  101 

about  four  minutes  more,  at  which  time  the  maximum  temperature  will 
have  been  reached.  The  radiation  for  this  period  is  found  as  follows : — 
Read  the  fall  in  temperature  for  each  minute  for  four  minutes  after  the 
maximum  has  been  reached.  The  average  drop  per  minute  represents 
the  correction  to  be  added  to  each  minute  preceding  the  maximum,  except 
for  the  minute  immediately  following  ignition.  The  final  temperature 
thus  corrected  for  radiation,  minus  the  initial  reading  before  ignition, 
represents  the  total  rise  in  temperature  due  to  the  reaction  in  the  cru- 
cible. 

Calculations: — From  the  total  rise  in  temperature,  corrected  for 
radiation  as  above  indicated,  subtract  the  correction  factors  for  the  heat 
due  to  the  chemical,  fuse-wire,  etc.,  as  indicated  under  "Correction 
Factors"  below,  and  multiply  the  remainder  by  3100.  The  product  will 
be  the  number  of  British  thermal  units  per  pound  of  coal.  (See  notes 
(a)  and  (b)  below.) 

It  is  to  be  noted  that  the  heat  value  as  derived,  refers  to  the  coal  in 
the  form  in  which  it  is  weighed  out  for  making  the  determination.  That 
is  to  say,  if  a  coal  having  5%  of  moisture  is  taken  and  %  gram  of  the 
same  weighed  out  and  dried  in  the  oven  at  212°  for  1  hour,  then  burned 
in  the  calorimeter,  the  result  obtained  refers  to  the  coal  on  the  basis  of 
5%  of  moisture  and  not  to  the  coal  as  in  the  oven-dry  state. 

To  calculate  values  to  "dry  coal,"  divide  the  number  by  100% 
minus  the  per  cent  of  moisture  present.  Thus,  a  coal  having  5% 
moisture  and  indicating  11000  B.  t.  u.  would  have  11000-=-.95=11579 
B.  t.  u.  on  the  "dry  coal"  basis. 

Note  (a),  Correction  Factors: — The  method  for  obtaining  the  cor- 
rection for  radiation  has  already  been  described  under  Temperature 
Readings.  The  other  correction  components  are  listed  for  convenient 
reference  as  follows : 

Electric  Fuse  Wire  equals 003°C.  or  .005°F. 

Per  cent  Ash  is  multiplied  by 0025°C.  or  .005°F. 

Per  cent  Sulphur  is  multiplied  by 005°C.  or  .010°F. 

1   gram   Accelerator  equals 150°  C.  or  .270°F. 

Hydration  Factors: 

For  all  Bituminous  Coals '. 040° C.  or  .070°F. 

For  Black  Lignites 056°C.  or  .100°F. 

Notefb):— The  factor  3100  is  deduced  as  follows:  The  water  used 
plus  the  water  equivalent  of  the  metal  in  the  instrument  amounts  to 
2123.3  grams.  In  the  reaction  73  per  cent  of  the  heat  is  due  to  com- 
bustion of  the  coal  and  27  per  cent  is  due  to  the  heat  of  combination  of 
CO2  and  H20  with  the  chemical.  If  now  %  gram  of  coal  causes  2123.3 
grams  of  water  to  rise  "r"  degrees,  and  if  only  73  per  cent  of  this  is 
due  to  combustion,  then  .73X2123.3X2X"r"=rise  in  temperature  which 


102         THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

would  result  from  combustion  of  an  equal  weight  (2123.3  grams)  of  coal. 
.73X2123.3X2=3100.00.  The  factor  2  is  used  instead  of  the  divisor 
0.5.  the  weight  of  coal  taken. 

To  Dismantle : — Remove  the  thermometer,  pulley  and  cover ;  then 
take  out  the  can  and  contents  entire,  so  that  the  lifting  out  of  the 
cartridge  will  not  drip  water  into  the  dry  parts  of  the  instrument. 
Remove  the  fusion  cup  and  place  it  on  its  side  in  the  bottom  of  a  beaker 
and  cover  with  hot  water.  After  the  fused  material  has  dissolved, 
remove  the  cup  and  rinse  thoroughly  with  hot  water.  Wash  the  face  of 
the  cap  and  electric  terminals  thoroughly.  For  this  purpose  a  jet  of 
hot  water  or  submerging  in  boiling  water  is  advisable,  as  the  metal  is 
thus  left  clean  and  hot,  the  latter  facilitating  the  drying  out  of  the  parts. 
Place  the  parts  on  a  radiator  or  near  a  hot  plate  to  insure  thorough 
drying. 

Anthracites  and  Coke: — In  the  case  of  anthracites  and  coke,  it  is 
well  to  use  0.2  grams  of  benzoic  acid  along  with  the  1  gram  of  accelera- 
tor and  y2  gram  of  fuel.  This  substance  facilitates  ignition  as  well  as 
the  ultimate  combustion.  The  heat  resulting  from  the  combustion  of 
this  extra  0.2  gram  of  benzoic  acid,  which  is  to  be  corrected  for  along 
with  the  other  correction  components,  is  1.550°  F. 

EXERCISE  VII.  ' 

For  Petroleum  Oils: — The  amount  of  oil  used  for  a  charge  should 
not  exceed  about  %  gram;  from  0.20  to  0.25  gram  giving  the  proper 
combustion.  The  weight  of  oil  is  best  obtained  by  means  of  a  small  light 
15  c.  c.  weighing  flask  provided  with  perforated  cork  and  dropping  tube 
with  common  rubber  bulb-cap.  Weigh  the  flask  and  contents,  and  by 
means  of  the  dropping  tube  discharge  20  to  30  drops  of  oil  and  re-weigh, 
thus  obtaining  the  weight  of  oil  taken  by  difference.  Determine,  by 
experiment,  the  height  in  the  dropping  tube  required  for  the  approx- 
imate amount  of  oil  desired  so  as  to  avoid  trial  weighings.  One  full 
measure  of  chemical  (sodium  peroxide)  and  1  gram  of  accelerator  are 
first  added  and  thoroughly  shaken  as  already  indicated.  Also,  to  facili- 
tate the  ignition  of  all  oils  and  at  the  same  time  promote  the  ultimate 
combustion,  it  is  recommended  that  a  small  amount  (0.2  gram)  of  ben- 
zoic acid  be  used  as  described  under  "Anthracites  and  Coke."  Add 
the  oil  and  benzoic  acid  last  and  mix  thoroughly  by  shaking  as  already 
indicated  and  complete  the  process  exactly  as  for  coal. 

Compute  by  means  of  the  formula  as  follows : 

Correcting  as  under  coals  for  radiation,  accelerator,  benzoic  acid 
and  fuse-wire,  and  letting  "r"  represent  the  rise  in  temperature;  then 

"r"X0.73X2123.3 

-  =B.  T.  U.  per  pound  of  oil. 
Wt.  of  oil 


HEAT  VALUE  OF  GASOLINE 


103 


Fig.  19 


EXERCISE  VIII. 

Gasolene,  Etc.: — For  gasolene,  benzine  and  very  volatile  liquids, 
the  difficulty  of  securing  an  accurate  weight  of  the  material  taken  is  met 
by  the  following  procedure:  By  the  use  of  very 
thin-walled  glass  tubing  of  about  5/32  inch  in 
diameter,  a  light  bulb  with  capillary  tip  may  be 
blown  of  approximately  the  size  and  shape  shown 
herewith,  Fig.  19.  After  a  little  practice  it  is  not 
difficult  to  blow  such  bulbs  to  weigh  less  than  0.2 
gram.  These  may  be  also  made  from  a  capillary 
obtained  by  softening  an  ordinary  piece  of  tubing 

in  the  flame,  and  drawing  out  the  same  to  a  filament  about  the  size  of 
a  knitting  needle.  By  fusing  the  end  of  such  filament,  bulbs  of  the 
desired  size  and  weight  may  be  blown.  When  so  blown,  they  may  be 
used  as  follows:  Weigh  the  bulb  carefully,  then  dipping  the  capillary 
end  into  the  liquid  and  alternately  warming  gently  and  cooling  the  bulb 
a  quantity  of  gasolene  is  drawn  into  the  bulb.  When  about  0.2  gram 
is  obtained,  seal  the  capillary  in  the  flame  and  weigh  accurately.  Add 
the  sodium  peroxide  and  accelerator  to  the  fusion  cup  first  and  thor- 
oughly mix  by  shaking  in  the  usual  manner.  Next  add  0.2  gram  of 
benzoic  acid  and  the  bulb  of  gasoline.  Put  on  the  ignition  top  and  clamp 
firmly  in  place  wTith  the  screw  cap.  Rotate  the  bomb  and  bring  it  into  an 
inverted  position,  shaking  lightly  at  first  to  bring  the  bulb  on  top  of  the 
chemical  and  nearest  the  bottom  of  the  fusion  cup.  Thus  inverted 
shake  the  bomb  vigorously  to  break  the  bulb,  then  assemble  in  the 
calorimeter  in  the  usual  manner.  In  calculating,  a  correction  is  neces- 
sary, in  addition  to  those  normally  observed,  on  account  of  the  heat  of 
fusion  due  to  the  glass  present.  This  amounts  to  0.03°  F.  for  each  0.1 
gram  of  glass  used  in  the  bulb.  This  should  be  subtracted  along  with 
the  correction  for  accelerator  and  fuse-wire.  The  corrected  rise,  "r," 
is  then  used  in  the  formula  as  above  given  for  petroleums. 

EXERCISE  IX. 

Sulphur: — Where  determinations  for  sul- 
phur are  to  be  made  independently  of  the  cal- 
orimetric  process,  a  special  apparatus  as  shown 
in  Fig.  20  is  employed.  The  charge  consists  of 
one  measure  of  sodium  peroxide  and  y2  gram 
of  coal.  Close  with  the  cover  and  screw  cap  and 
shake  thoroughly.  Ignite  the  charge  by  apply- 
ing the  flame  of  a  Bunsen  burner  to  the  bottom 
of  the  fusion  cup  for  a  moment.  Remove  the 
flame  as  soon  as  the  reaction  has  commenced, 
which  will  be  indicated  by  the  lower  portion  of 


300 


Fig.  20 


104         THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

the  cup  betcoming  a  dull  red.  After  the  charge  has  ignited,  the  bomb 
may  be  cooled  without  delay  by  holding  under  the  tap  or  submerging 
in  water.  If  the  cover  is  fitted  with  a  rubber  gasket,  the  cooling  with 
water  should  follow  very  soon  after  the  ignition.  If  an  asbestos  gasket 
is  used,  the  cooling  may  be  attended  to  at  leisure.  The  use  of  a  rubber 
gasket  is  preferred,  as  it  does  not  disintegrate  on  washing.  The  dis- 
mantling and  dissolving  out  the  fusion  from  the  cup  is  carried  out  in 


Fig.  21.     Sulphur  Photometer. 

the  usual  manner  as  already  described.  The  solution  is  neutralized 
with  chemically  pure  hydrochloric  acid  and  1  c.  c.  of  the  concentrated 
(1.19  sp.  g.)  acid  added  in  excess.  The  bulk  of  the  solution  should  be 
about  300  c.  c.  From  this  point  the  sulphur  as  S03  is  determined  in 
the  regular  manner,  either  by  the  gravimetric  or  photometric  process. 
The  Photometric  Process: — Transfer  the  slightly  acid  solution  to 
the  250  c.  c.  flask  and  make  up  to  the  mark.  Mix  thoroughly  and  meas- 
ure out  for  analysis  50  c.  c.  of  the  solution  into  the  cylinder  G,  Fig.  21, 
and  50  c.  c.  of  distilled  water  so  that  the  final  volume  shall  be  100  c.  c. 


THE  PHOTOMETRIC  DETERMINATION  OF  SULPHUR  105 

Transfer  the  100  c.  c.  of  solution  from  the  cylinder  to  the  Erlenmeyer 
flask  E,  add  0.3  to  0.5  gram  of  Special  Barium  Chloride  Powder,*  and 
without  delay  close  the  flask  with  the  cork  and  shake  vigorously  for  one 
or  two  minutes,  then  allow  to  stand  at  room  temperature,  with  occasional 
shaking,  for  15  to  20  minutes. 

In  reading  the  turbidity,  the  solution  is  shaken  and  a  portion 
poured  from  the  Erlenmeyer  flask,  E,  into  the  wide  mouthed  dropping 
funnel,  F.  The  graduated  tube,  A,  is  adjusted  in  the  dark  tube  so  that 
the  rounded  lower  end  dips  well  into  the  water  in  the  flat  bottomed  dish, 
B,  which  should  be  about  y2  inch  in  depth.  Adjust  the  flame  to  a  height 
of  1  inch.  This  is  accomplished  by  having  the  tip  appear  about  %  of 
an  inch  above  the  edge  of  the  metal  chimney.** 

By  means  of  the  pinch  cock  admit  the  turbid  solution  until  the  point 
of  light  from  the  candle  flame,  L,  just  disappears,  the  last  point  of  light 
from  the  flame  being  no  longer  visible.  Do  not  take  account  of  the 
slightly  luminous  center  that  appears  when  the  amount  of  sulphur  is 
high  and  the  readings  are  on  the  lower  portion  of  the  scale,  say  from  40 
to  60  mm.  Take  as  the  end  point  the  disappearance  of  the  point  of  light. 
Remove  the  tube  and  read  in  milligrams  the  depth  of  the  liquid.  By 
means  of  the  table  or  curve  is  shown  the  weight  in  milligrams  of  the 
sulphur  present  in  the  100  c.  c.  of  solution.  If  50  c.  c.  were  taken  from 
the  250  c.  c.  flask,  and  this  latter  contained  the  fusion  from  a  y2  gram 
sample  of  coal,  then  the  sulphur  reading  would  be  the  weight  present  in 
1/10  gram  of  coal.  By  removal  of  the  decimal  point,  therefore,  one  place 
to  the  right,  there  would  be  shown  the  weight  of  sulphur  in  one  gram,  of 
coal  which  can  then  be  read  in  parts  per  100,  or  per  cent,  by  placing  the 
decimal  two  more  places  to  the  right.  If  read  in  milligrams  each  unit 
is  then  1  per  cent. 

For  example,  if  the  results  show  a  depth  of  105  millimeters,  there 
would  be  indicated  1.93  milligrams  of  sulphur  present  in  the  quantity 
taken,  that  is  0.00193  grams.  Now,  if  %  of  the  %  gram  of  coal  is  repre- 
sented in  this  amount,  the  reading  is  for  1/10  gram  of  coal.  For  1  gram 
of  coal  there  would  then  be  0.0193  gram  of  sulphur,  or  1.93per  cent. 

If  the  sulphur  is  so  great  in  amount  as  to  afford  too  great  turbidity 
for  satisfactory  reading,  repeat  the  process,  measuring  out  25  c.  c.  of 
the  solution  and  diluting  with  water  sufficient  to  make  a  total  of  100 
c.  c.  in  volume,  and  proceed  as  above  outlined.  After  multiplying  the 

*The  Special  Barium  Chloride  Powder  is  composed  of  equal  parts  of  Barium 
Chloride  (BaCl2)  and  Oxalic  Acid  (H^O*).  By  trial  measurement  on  the  point 
of  a  spatula  and  weighing  a  few  times,  the  amount  of  powder  by  bulk  can  be 
readily  determined  with  sufficient  accuracy. 

**A  small  3-volt  tungsten  bulb  with  current  from  2  dry  cells  gives  a  more 
satisfactory  light.  The  readings  check  with  those  obtained  with  the  gas  flame 
so  that  the  same  curve  may  be  used. 


106         THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

weight  of  the  sulphur  thus  indicated  by  2,  the  conditions  will  be  the 
same  as  indicated  in  the  paragraph  above. 

In  cases  where  the  content  of  sulphur  in  the  coal  is  so  low  that  the 
reading  on  the  tube  comes  above  the  limit  of  graduation,  a  larger 
quantity  of  the  solution  representing  a  greater  amount  of  coal  should 
be  taken.  Thus,  if  we  take  100  c.  c.  of  the  solution,  we  will  be  taking1 
%  of  %  gram  of  the  original  coal  or  %  (.2)  gram  of  coal.  Now,  the 
sulphur  indicated  on  the  curve  will  be  the  weight  in  milligrams  which 
accompanies  0.20  gram  of  coal.  If,  therefore,  we  read  the  percentage 
as  normally  indicated  and  divide  by  2;  we  will  have  the  correct  indica- 
tion for  the  content  of  sulphur.  For  example,  if  the  reading  under  these 
conditions  shows  a  depth  of  105  m.  m.  there  would  be  indicated  1.93 
milligrams  of  sulphur  for  the  amount  of  coal  taken,  0.2  grams.  This 
would  be  0.965  milligrams  for  0.20  gram  of  coal,  or  0.96  per  cent.* 

Special  care  must  be  taken  to  prevent  the  settling  out  of  the  pre- 
cipitate. A  reading  can  be  quickly  made  and  the  contents  of  the  tube 
poured  back  into  the  funnel.  Readings  should  be  repeated  several  times, 
thus  keeping  the  mixture  stirred  and  affording  greater  accuracy  as  to 
the  final  average  taken.  Before  beginning,  the  bottom  of  the  tube  inside 
should  be  cleansed  by  means  of  a  swab  to  insure  that  no  film  of  pre- 
cipitate from  the  previous  test  has  settled  out. 

The  diaphragm  between  the  dark  cell  and  the  candle  prevents 
moisture  from  forming  on  the  bottom  of  the  water  cup.  Notice  should 
be  taken,  however,  as  to  this  point;  and,  in  case  of  a  film  of  moisture 
forming,  it  may  be  prevented  by  warming  the  water  used  in  the  cub  a 
little  above  the  room  temperature.  For  the  same  reason  be  sure  that  no 
sediment  has  settled  out  on  the  bottom  of  the  cup,  B.  Perfect  alignment 
of  the  flame  through  the  diaphragm  and  tube  should  be  secured.  The 
conditions  as  to  strength  of  light,  methods  of  reading,  the  end  point,  etc., 
may  vary  from  the  standards  adopted  in  the  table.  Each  individual 
may  easily  check  his  own  method  by  making  up  a  solution  of  chemically 
pure  sulphuric  acid,  having  0.5438  gram  per  liter,  which  is  equivalent 
to  0.0001  gram  of  sulphur  per  c.  c.  Use  15  or  20  c.  c.  in  making  the  test. 

Note: — In  tabulating  the  results  of  coal  analysis  remember  that  the 
constituent  percentages  in  the  case  of  each  condition  of  reference  should 
total  100  per  cent;  this  also  excluding  the  factor  for  sulphur,  which  in 
the  process  of  proximate  analysis  is  a  constitutent  part  of  certain  com- 
ponents, approximately  %  going  with  the  volatile  matter  and  %  remain- 
ing with  the  coke. 

*Some  coals,  especially  of  the  semibituminous  or  Pocahontas  type,  have  a 
content  of  sulphur  so  low  as  to  make  it  advisable  in  such  cases  to  dissolve  the 
fusion  in  a  smaller  quantity  of  water,  so  that  the  volume  when  made  up  shall  be 
100  c.c.  With  sulphur  so  low  as  0.5  per  cent  the  entire  solution  would  be  required 
for  use  with  the  photometer. 


CHART  FOR  SULPHUR  READINGS 


107 


53  52  3.1    3.0  ~2.<?  2.8  2.7  2.6  2.5  2.4  23  2.2 


2.0    Ifl    1.8    L7    J.6    15    1.4 


MILLIGRAMS    OF    SULPHUR 

Fig.  22.     Curve  showing  the  weight  of  sulphur  in  milligrams 


1.2 


io8         THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


Fig.  23 
Oxygen  Bomb 

EXERCISE  X. 

Heat  Values  ly  the  Oxygen  Bomb  Calorimeter: — Figure  23  shows 
the  arrangement  of  the  parts  of  the  bomb  when  ready  for  placing  in  the 
calorimeter.  When  the  calorimeter  is  dismantled  the  double  cover  to 
the  insulating  chamber  is  supported  on  a  ring-stand  as  shown  in  the  cut, 
Fig.  2,  Part  I.  This  affords  a  convenient  method  of  handling  the  stirring 
device  and  insures  greater  safety  for  the  thermometer. 


MANIPULATION  OF  THE  OXYGEN  BOMB 


109 


When  the  bomb  is  opened  and  made  ready  to  receive  the  charge  of 
fuel,  the  cap  is  most  conveniently  held  on  the  ring-stand  which  accom- 
panies the  instrument.  Thus  supported,  the  fuel  capsule  and  fuse  wire 
are  readily  adjusted  as  shown  in  Fig.  24.  For  coal,  one  gram  of  the 


Fig.  24 
Holders  for  Filling  and  Adjusting  the  Fuse  Wire. 

air-dry  sample,  ground  to  pass  a  60  mesh  sieve,  is  weighed  in  the  capsule 
43 A,  Fig.  23.  Attach  the  ignition  wire  to  the  terminals,  4 A  and  5 A,  by 
passing  one  end  thru  the  eyelet  of  one  of  the  terminals  so  it  will  extend 
beyond  the  eyelet  about  *4-  inch.  Wrap  the  free  wire  around  the  term- 
inal at  the  narrow  portion  formed  by  the  notch,  giving  it  three  turns, 
binding  in  the  free  end  and  bending  the  wire  finally  downward  in  line 
with  the  terminal.  Repeat  the  same  process  with  the  other  end  of  the 
wire.  The  fuse  wire  should  be  about  7  cm.  long.  That  part  of  the 
wire  between  the  terminals  should  be  bent  into  a  somewhat  narrow  U 
shaped  loop  so  that  the  fuse  wire  will  not  touch  the  sides  of  the  capsule. 
Adjust  the  wire  so  that  the  lower  part  of  the  fuse  loop  will  just  touch  the 
surface  of  the  coal. 


no         THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

Transfer  the  cover  to  the  bomb,  in  which  a  half  cubic  centimeter  of 
water  has  been  placed  for  taking  up  the  acids  formed  in  the  process  of 
combustion.  The  bomb  should  rest  in  the  octagon  holder  for  filling. 
Screw  on  the  cap,  3A.  In  sealing,  apply  the  large  wrench,  using  good, 
firm  pressure,  though  only  moderate  force  is  necessary  for  securing  a 
perfect  seal  at  the  rubber  gasket,  54 A. 

For  filling  with  oxygen,  connection  is  made  with  the  flexible  copper 
tubing  and  oxygen  is  admitted  until  a  pressure  of  25 — 30  atmospheres 
is  indicated.  In  admitting  the  oxygen  the  needle  valve  next  to  the  pres- 
sure gauge  is  opened  slightly  to  avoid  a  sudden  rush  of  gas.  After  a 
sufficient  amount  has  been  admitted,  close  the  needle-valve  and  open 
the  pet-cock  below  the  gauge  in  order  to  release  the  oxygen  under  pres- 
sure in  the  tube  and  connections.  The  check  valve,  11A — Fig.  23,  auto- 
matically closes  and  retains  the  oxygen  at  the  desired  pressure. 

Transfer  the  bomb  carefully,  without  jarring,  to  the  oval  can  which 
has  been  placed  in  position  in  the  calorimeter.  The  long  axis  of  the  oval 
should  be  in  line  with  the  operator,  that  is,  at  right  angles  to  the  work 
desk.  The  pointer,  57A — Fig.  25,  and  a  notch  in  the  can  directly  oppo- 
site, serve  as  guides  for  correctly  locating  the  vessel.  The  circular  eleva- 
tion in  the  bottom  which  directs  the  locating  of  the  bomb  should  be 
toward  the  operator.  Turn  the  bomb  so  that  one  of  the  faces  of  the 
octagon,  rather  than  an  angle,  will  be  toward  the  operator,  thus  giving 
more  room  for  the  thermometer.  Make  the  connection  with  the  electric 
terminal,  58A,  and  add  2000grams  of  water,  preferably  distilled.  The 
temperature  of  the  water  should  be  2°  or  3°  Fahrenheit  below  that  of 
the  room. 

In  placing  the  cover  on  the  calorimeter  have  the  thermometer 
toward  the  operator.  This  will  bring  the  pulley  with  turbine  stirrer  at 
the  back  of  the  instrument.  Bring  the  cover  to  place  carefully  so  as  to 
avoid  striking  the  thermometer  against  the  metal  parts  (see  Fig.  25). 
Seat  the  spring  clips  for  holding  the  cover  firmly  in  place  and  connect 
the  pulley  with  the  motor.  The  motor  is  adjusted  so  as  to  give  the  tur- 
bine pulley  a  speed  of  about  150  revolutions  per  minute  turning  to  the 
right  or  clockwise.  A  uniform  speed  throughout  a  determination  is 
desirable. 

By  use  of  the  telescopic  lens,  readings  of  the  thermometer  for  the 
preliminary  period  are  taken  at  one  minute  intervals  for  five  minutes. 
At  the  fifth  reading  close  the  electric  circuit  for  a  second  or  not  to  exceed 
two  seconds.  Ignition  of  the  sample  should  be  indicated  by  a  rise  of  the 
mercury,  which  becomes  rapid  after  20  or  30  seconds.  The  combustion 
period  extends  over  5  or  6  minutes  and  terminates  when  the  maximum 
temperature  has  been  reached,  or  when  the  rate  of  change  has  become 
uniform.  The  final  period  follows  the  combustion  period.  Eeadings  are 
taken  at  minute  intervals  for  five  minutes. 


RADIATION  CORRECTIONS  AND  COMPUTATIONS  in 

OBSERVATIONS* 

During  the  ignition  period,  if  the  temperature  rise  for  the  sample 
in  hand  is  not  approximately  known,  take  thermometer  readings  at  40, 
50  and  60  seconds  after  firing. 

Make  the  following  notations : 

(1)  The  rate  of  rise  (r)  for  the  preliminary  period  in  degrees  per  minute. 

(2)  The  time   (a)   at  which  the  last  reading  of  the  preliminary  period  is  made, 
immediately  before  firing. 

(3)  The  time    (b)    when  the  rise  of  temperature  has  reached  six-tenths  of  its 
total  amount.     This  point  can  generally  be  determined  by  adding  to  the  tem- 
perature reading  at  the  time  of  firing  60  per  cent  of  the  expected  temperature 
rise  and  noting  the  time  (b)  when  this  point  is  reached.     If  the  approximate 
temperature  rise  is  not  known,  six-tenths  of  the  total  rise  as  subsequently 
developed,  when  added  to  the  temperature  reading  at   (a),  will  indicate  the 
time    (b)    by  interpolating  readings   obtained   at   the   50,  60,   and   70  second 
periods  after  firing. 

(4)  The  time    (c)   when  the  maximum  temperature  has  been  reached,  or  when 
the  rate  of  change  has  become  uniform,  usually  about  five  minutes  after  firing. 

(5)  The  rate  of  change  (r2)  for  the  final  period  in  degrees  per  minute. 

COMPUTATIONS 

Apply  the  corrections  as  indicated  on  the  thermometer  certificate 
for  the  initial  (a)  and  final  (c)  readings. 

Multiply  the  rate  (rx)  by  the  time  (b — a)  in  minutes  and  tenths  of 
a  minute  and  add  the  product  to  the  corrected  temperature  reading  at 
time  (a). 

Multiply  the  rate  (r,)  by  the  time  (c — b)  and  add  (or  subtract  if 
the  temperature  was  rising  during  the  final  period)  the  product  to  the 
corrected  temperature  reading  at  time  (c). 

The  difference  of  the  two  readings  thus  modified  to  account  for  radi- 
ation corrections  gives  the  total  rise  of  temperature  due  to  combustion. 

Multiply  the  total  rise  thus  found  by  the  water  equivalent  of  the 
calorimeter,  the  product  giving  the  total  amount  of  heat  liberated.  If 
the  thermometer  readings  were  in  Fahrenheit  degrees  the  product  gives 
the  heat  value  in  B.  t.  u. 

*See  report  of  Committee  on  Methods  of  Coal  Analysis,  Journal  of  Industrial 
and  Engineering  Chemistry,  Vol.  5,  p.  517  (1913). 


ii2          THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC 

CORRECTIONS 

The  heat  produced  by  the  formation  of  nitric  acid  from  the  nitro- 
gen in  the  oxygen  and  sulphuric  acid  from  the  sulphur  in  the  combust i- 


Fig.  25 
Oxygen  Bomb  Calorimeter 

ble  is  corrected  for  by  washing  the  bomb  thoroughly  with  distilled  water 
after  the  determination  is  completed  and  titrating  the  washings  with  a 
solution  of  sodium  carbonate. 


CORRECTIONS  113 

Make  up  the  sodium  carbonate  solution  by  dissolving  2.061  grains 
chemically  pure  Na2C03  in  one  liter  of  distilled  water.  One  cc=l 
B.  t.  u.  for  the  formation  of  nitric  acid. 

The  sulphuric  acid  formed  has  produced  an  equivalent  of  heat  in 
excess  of  the  correction  applied  as  for  nitric  acid  equal  to  9§  times  the 
sulphur  content  expressed  in  per  cent. 

Iron  wire  of  No.  34  American  Gauge  produces  heat  at  the  rate  of 
4  1/2  B.  t.  u.  for  each  centimeter  of  wire  burned.  A  correction  should, 
therefore,  be  made  for  the  length  of  wire  actually  consumed.  Subtract 
the  unburned  portion  remaining  on  the  terminals  from  the  original 
length  in  centimeters  and  multiply  the  remainder  by  4  1/2,  the  result  is 
the  correction  in  B.  t.  u.  for  the  wire  consumed. 

Finally  note  that  the  total  indicated  heat  as  corrected  for  nitric 
acid,  sulphuric  acid  and  fuse  wire  refers  to  a  quantity  of  fuel  repre- 
sented by  the  weight  of  the  charge  taken.  If  this  weight  were  exactly  1 
gram  no  further  computation  is  necessary.  If  the  weight  taken  varied 
from  an  even  gram,  the  indicated  B.  t.  u.  as  above  derived  must  be 
divided  by  the  weight  of  fuel  taken. 

To  discharge  the  oxygen  from  the  bomb,  press  down  the  valve,  13A, 
with  the  thumb  to  release  the  gas.  Do  not  try  to  remove  the  screw  cap, 
3A,  until  after  the  gas  pressure  has  been  released. 

Upon  opening  examine  the  interior  for  unburned  carbon.  If  any 
is  found  reject  the  experiment. 

To  standardize  the  instrument,  make  a  combustion  using  a  stand- 
ard substance  of  known  heat  value  as  pure  benzoic  acid.  Add  to  the  ac- 
cepted heat  value  of  the  quantity  taken,  say  1.  gram,  the  heat  due  to  the 
combustion  of  the  wire  and  the  nitric  acid  formed.  Divide  the  heat 
value  thus  represented  by  the  temperature  rise,  corrected  in  the  usual 
manner.  The  quotient  represents  the  total  water  equivalent  made  up 
to  the  actual  grams  of  water  employed,  2000  plus  the  equivalent  in  water 
of  the  metal  parts,  etc.,  of  the  apparatus. 


ii4         THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


EXAMPLE  OF  COMPUTATIONS 
Lab.  No.  7968 
Weight  of  material  burned     .8  grams 


Date — June  29,  1914 
Room  Temp.  23.7  °C. 


Sulphur  in  coal 4.31% 

Time                      Temperature 
2-1 1 295 

12 299 

13 303 

14 307 

15 310 

(a)  16 313 

Fired 

(b)  17-12 1.573* 


O°  of  Beckman  Ther.  2i.8°C. 
Water  Eqv.  2416  gram. 


.018 

5 


>ri  =    -     —  =  0.0036 


Initial  temp. 
Certif.  Corr.    — 
Corr.  initial 


0.313 
.001 


.312 


Final 
Corr. 
Final 


2.399 

.009 

2.408 


r2  = 


.005 
S 


=  O.OOI 


21 2.399 

22 2.398 

23 2.397 

24 2.397 

25 2.395 

26 2.394 

(b  -  a)   X  n  =  1. 12  X  .0036 0.004 

(c  -  b)   X  r2  =  3.48  X     .001 


.0.003 


316 


2.411 
.316 


Setting  Corr. 
Stem 
Corrected  rise. 


2.095 

O.OOI 
O.OOI 


Total    Calories  —  2416  X  2.097  =  5066.4 
Acidity  titration  =  27.2  Cal. 
Corr.  for  wire    =  18.4    " 
Sulphur   Corr.     =44.8    "  90.4 


.2.097 


Calories   from   .8  gram  =  4976. 
Calories   per  gram     =      6620. 


*The    initial    temperature    is     0.313 
60%  of  the  expected  rise  is     1.260 

The  time  to  observe  then  is     1.573 

Note  a: — For  anthracite  coal  a  thin  pad  of  asbestos  felt  should  be  formed  on 
the  inside  of  the  capsule.  Take  a  small  amount  of  asbestos  pulp,  squeeze  out  the 
water  and  form  a  felt  on  the  bottom  and  sides  of  the  capsule,  then  dry  and  ignite. 
This  will  prevent  the  lowering  of  the  temperature  below  the  ignition  point  before 
combustion  is  complete. 


ULTIMATE  ANALYSIS 


Note  b: — To  insure  against  loss  of  oxygen  thru  leakage  it  is  well  to  keep 
the  needle-valve  between  the  gauge  and  the  oxygen  cylinder  and  also  the  valve  on 
top  of  the  cylinder  closed  when  not  drawing  out  oxygen.  For  filling  the  bomb, 
open  f.rst  the  cylinder  valve  slightly,  then  open  the  needle-valve  gradually,  regulat- 
ing the  flow  by  noting  the  gauge  indicator. 

Note  c: — Do  not  attempt  to  displace  the  air  in  the  bomb  with  oxygen  before 
filling.  A  certain  amount  of  nitrogen  is  necessary  for  the  complete  oxidation  of 
the  sulphur.  (See  Vol.  6.,  p,  812,  Journal  of  Industrial  and  Engineering  Chemistry). 

CHAPTER   VIII 
ULTIMATE    ANALYSIS    OF    COAL 

Total  Carbon  Determination: — The  percentage  of  total  carbon  in 
the  coal  used  is  a  necessary  factor  in  determining  the  heat  losses  in  the 


/ 


FIG.  26 

flue  gases  as  already  indicated  in  the  calculations  on  pages  73  to  76 
inclusive.    This  value  may  be  obtained  by  making  an  ultimate  analysis 


ii6         THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

which  consists  essentially  in  burning  a  sample  of  the  coal  in  a  current 
of  oxygen,  absorbing  the  C02  formed  in  a  solution  of  potassium  hydrox- 
ide, and  obtaining  the  amount  of  C02  formed  by  direct  weighing.  A 
more  convenient  method  makes  use  of  the  fusion  resulting  from  the 
calorimetric  determination  using  sodium  peroxide.  As  a  result  of  the 
reaction,  all  of  the  carbon  of  the  coal  is  present  in  the  fusion  as  sodium 
carbonate,  Na2C03.  By  treating  with  acid,  therefore,  in  a  suitable  appa- 
ratus, the  C02  is  delivered  in  a  form  to  be  measured  by  volume  as  shown 
in  Fig.  26. 

The  apparatus  should  be  located  on  a  laboratory  desk  or  table 
where  an  even  temperature  can  be  maintained. 

Fill  the  jacketing  tube  "J"  with  water  slightly  acidulated  to  keep 
it  clear.  Fill  the  leveling  tube  "L"  with  Avater  that  has  had  two  or 
three  c.c.  of  sulphuric  acid  added.  A  few  drops  of  methyl-orange  in  the 
leveling  tube  will  impart  a  color  to  the  water,  greatly  facilitating  the 
readings. 

Connect  the  inlet  "D"  with  air  pressure  and  adjust  so  that  two  or 
three  bubbles  of  air  per  second  will  enter  the  jacketing  water.  This  is 
for  the  purpose  of  keeping  the  temperature  of  the  water  equalized 
throughout  a  determination.  By  reading  the  thermometer  hung  in  the 
water  the  temperature  of  the  gas  under  observation  is  obtained. 

The  operation  is  as  follows : — The  large  double  pipette  "  P "  is  half 
filled  with  40  per  cent  solution  of  caustic  potash,  or  such  as  is  ordinarily 
used  for  the  absorption  of  C02  gas.  By  turning  the  three-way  cock  "T" 
to  connect  with  the  pipette  "P"  and  lowering  the  leveling  tube  "L" 
the  liquid  in  "P"  is  brought  into  the  right  hand  bulb  and  made  to  rise 
in  the  capillary  tube  to  the  mark  on  the  right  limb  of  the  capillary. 
The  three-way  cock  is  now  closed  to  the  pipette  bulb  and  opened  to  the 
tube  running  to  the  flask  "B".  By  raising  the  leveling  tube  "L"  the 
liquid  in  the  burette  "G"  is  made  to  rise  to  the  three-way  cock  "T", 
thus  completely  filling  the  burette.  The  three-way  cock  is  now  closed 
to  retain  the  liquid  in  the  burette  at  the  zero  point,  till  evolution  of  the 
gas  is  begun. 

The  cup  containing  the  fused  material  from  a  calorimetric  determi- 
nation is  placed  on  its  side  in  the  bottom  of  a  small  beaker  and  covered 
with  hot  water  that  has  been  boiling  for  5  or  10  minutes.  When  the 
fusion  is  dissolved  remove  the  cup,  rinsing  it  well,  and  pour  the  solution 
directly  into  the  flask  "B".  Wash  out  the  beaker  thoroughly  with  hot 
water  and  pour  the  washings  in  with  the  main  portion.  Connect  with 
the  funnel  tube  ''A"  and  bring  the  ring  support  with  wire  gauze  in 
place  under  the  flask.  Open  the  stop  cock  at  the  lower  end  of  the  funnel 
and  boil  the  contents  of  the  flask  for  3  or  4  minutes.  Remove  the  flame 
and  at  once  close  the  funnel  cock.  In  this  way  the  oxygen  from  the 


DETERMINATION  OF  TOTAL  CARBON  117 

sodium  peroxide  will  be  driven  off  together  with  the  air  in  the  flask. 
Also,  since  the  three-way  cock  "T"  is  closed  there  will  be  a  partial 
vacuum  in  the  flask. 

With  the  cock  to  the  funnel  tube  "A"  closed,  enough  acid  is  added 
to  "A"  to  completely  neutralize  the  alkaline  solution  in  "B"  and  leave 
a  distinct  excess  of  acid.  Either  hydrochloric  or  sulphuric  acid  may  be 
used.  Thirty  cubic  centimeters  of  concentrated  hydrochloric  acid,  or 
15  c.c.  of  a  solution  of  concentrated  sulphuric  acid  and  water  in  the 
proportion  of  1 :1  will  be  found  sufficient. 

To  operate,  lower  the  leveling  tube  "L",  open  the  three-way  cock 
"T"  to  the  tube  connecting  with  the  flask  "B"  and  admit  acid  drop 
by  drop  from  the  funnel  "A".  Meantime  the  circulating  water  for  the 
condenser  "C"  should  be  turned  on. 

When  the  evolution  of  gas  has  about  reached  the  capacity  of  the 
graduated  burette  "G",  the  acid  is  shut  off,  the  three-way  cock  "T" 
closed  and  a  reading  of  the  volume  of  the  gas  carefully  taken  by  bringing 
the  two  surfaces  of  liquid  in  the  leveling  tube  and  burette  exactly  on  a 
level.  Read  also  the  temperature  of  the  jacketing  water  and  note  the 
barometric  pressure.  The  cock  "  T "  is  now  opened  to  the  capillary  and 
the  gas  volume  forced  completely  over  into  the  bulb  "P"  where  it  is 
held  by  closing  the  cock  "T".  Here  it  is  left  for  complete  absorption 
of  the  C02.  The  cock  "T"  may  be  again  opened  to  connect  with  the 
flask  "B",  the  liquid  in  the  burette  "G"  being  at  the  zero  point  as 
before.  The  apparatus  is  now  ready  for  a  second  evolution  and  meas- 
urement of  a  gas  volume. 

A  second  reading  is  similarly  taken  and  the  volume  driven  over  into 
"P"  as  before,  along  with  the  former  volume. 

Finally  heat  is  added  to  the  flask  "B"  and  after  a  few  minutes 
boiling,  hot  water  is  added  through  the  funnel  "A",  until  the  entire 
space  in  "B"  to  the  three-way  cock  "T"  is  filled.  The  flame  of  course 
being  removed. 

The  various  readings  should  be  so  adjusted  that  this  final  process 
will  produce  a  volume  sufficiently  large  to  bring  the  same  down  upon 
the  graduated  portion  of  the  burette  for  reading. 

Finally  the  residual  gas  in  "P",  after  the  complete  absorption  of 
the  C02,  is  returned  to  the  burette  "G"  and  the  volume  read.  The  dif- 
ference between  this  volume  and  the  total  of  the  several  volumes  is  the 
total  carbon  dioxide  present  in  the  fusion. 

By  referring  to  Table  XIX  there  is  found  at  the  observed  tempera- 
ture and  pressure  the  weight  in  milligrams  of  carbon  in  one  cubic  centi- 
meter of  C02  gas.*  Multiply  this  weight  by  the  number  of  cubic  centi- 

*See  also  "The  Weight  of  Carbon  Dioxide  with  a  Table  of  Calculated 
Values."  S.  W.  Parr,  Journal  American  Chemical  Society,  Vol.  XXI,  p.  237,  1909. 


ii8          THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

TABLE  XIX 


CM 

O 


u. 
o 


o 

CD 

a 


u 


I    CO    * 

2  <  5 

Sg  ? 


OJ 


rO 


ro 


in 


in 


cr> 


r-    oo 


t 


S. 


f 


CVJ 


f\ 


CO 
CVJ      (\J 


TOTAL  HYDROGEN  119 

meters  obtained  in  the  above  operation  and  the  product  equals  the 
weight  in  milligrams  of  pure  carbon.  From  this  should  be  subtracted 
the  weight  of  carbon  found  by  running  a  blank  in  exactly  the  same 
manner,  using  one  measure  of  the  sodium  peroxide  instead  of  the  fusion. 

After  subtracting  the  blank,  the  carbon  remaining  represents  the 
total  carbon  present  in  the  fuel.  Divide  this  number  by  the  weight  of 
fuel  taken  and  multiply  by  100.  The  product  is  the  per  cent  of  carbon 
present  in  the  sample  taken. 

Xote:  The  fusion  and  alkaline  solution  should  be  covered  and  kept  free 
from  circulating  air,  so  as  to  avoid  absorption  of  CO.. 

Hydrogen: — In  the  calculations  for  deriving  a  heat  balance,  the 
engineer  requires  the  factor  for  the  total  hydrogen  in  the  coal  used. 
The  hydrogen  present  is  considered  as  combined  in  two  different  ways. 
In  one,  the  hydrogen  is  "disposable"  or  "available"  for  combustion. 
In  the  other  it  is  supposed  to  be  joined  with  oxygen  to  form  H20  and 
when  thus  combined  is  not  available  for  the  production  of  heat.  The 
available  hydrogen  may  be  derived  as  follows :  If  we  let  C  represent 
the  percentage  of  total  carbon,  then  14544C  will  equal  the  heat  value 
for  that  constituent.  To  this  add  the  heat  value  of  the  sulphur  present, 
4500S.  The  remainder  of  the  heat  is  due  to  the  combustion  of  hydrogen. 
Hence,  with  a  value  for  hydrogen  of  62,100  the  percentage  of  available 
hydrogen,  H,  will  be  represented  by  the  expression : — 

H  B.t.u  -  -  (14544C  +  4500S; 

62,000 

The  hydrogen  not  available  or  considered  to  be  in  combination  with 
oxygen  is  estimated  as  %  of  the  oxygen  or  0/8  as  in  Dulong's  formula. 
There  is  required,  therefore,  the  percentage  of  oxygen  and  this  is  deter- 
mined by  difference.  That  is,  if  we  subtract  from  100  the  values  for 
ash,  sulphur,  total  carbon,  available  hydrogen,  and  nitrogen,  the  differ- 
ence will  be  the  non-available  hydrogen  and  oxygen  present  in  the  ratio 
of  H2  :  0.  Hence  1/9  of  this  difference  is  H2  and  8/9  is  the  oxygen 
percentage.  That  is,  the  per  cent  of  chemically  combined  water  is  rep- 
resented by  the  formula : — 

H20  =  100  —  ( A  +  S  +  C  +  available  H  +  N) 

The  only  undetermined  factor  in  the  above  expression  is  that  for 
nitrogen.  It  may  be  determined  directly  by  the  Kjeldahl  method,  or, 
for  purposes  of  calculating  a  heat  balance  it  is  quite  sufficiently  accurate 
to  assume  a  value  of  1  per  cent  for  nitrogen,  since  the  amount  present 
in  bituminous  coals  varies  only  within  relatively  narrow  limits,  say  from 
0.75  to  1.50  per  cent. 


CHAPTER  IX 
THE  ANALYSIS  OF  FLUE  GASES 

Reagents: — The  analyses  to  be  made  in  this  course  will  be  performed 
with  what  is  known  as  the  "Orsat  apparatus."  This  is  made  of  a  jack- 
eted 100  c.c.  gas  burette  and  leveling  bottle  permanently  connected  by  a 
capillary  tube  having  four  side  arms  to  three  pipettes  and  to  the  open 
air.  The  end  of  the  capillary  tube  extends  outside  the  case  for  conven- 
ience in  taking  a  sample  of  gas.  The  pipettes  are  provided  with  re- 
agents, as  follows : 

1.  Potassium  Hydroxide,  for  absorption  of  carbon  dioxide,  C02. 
Strength  of  solution,  50%.     One  c.c.  absorbs  40  c.c.  of  carbon  dioxide. 

2.  Potassium  Pyrogallate,  for  absorption  of  oxygen,  02.    Dissolve 
5  grams  of  pyrogallic  acid  in  20  c.c.  of  water  and  pour  into  the  proper 
pipette.     Next  dissolve  120  grams    (approximately)    of  potassium  hy- 
droxide (KOH),  in  80  c.c.  of  water  and  add  to  the  same  pipette.    Keep 
protected  from  the  air.    One  c.c.  absorbs  2  c.c.  of  oxygen. 

3.  Cuprous   Chloride,   for   absorption   of   carbon   monoxide,    CO. 
This  may  be  prepared  in  two  ways :     ( 1 )  by  keeping  a  bottle  full  of  hy- 
drochloric acid  (1.10  sp.  gr.)   having  copper  oxide  in  the  bottom  and 
much  copper  wire  in  it,  or,   (2)   shake  together  in  a  closed  flask  200 
grams  commercial  cuprous  chloride  and  a  solution  containing  250  grams 
ammonium  chloride  in  750  c.c.  of  water.     Add  enough  ammonium  hy- 
droxide to  bring  the  cuprous  chloride  completely  into  solution.     This 
will  require  about  1  volume  of  ammonium  hydroxide  solution  ,sp.  gr. 
0.90)  to  4  volumes  of  the  solution.   Keep  protected  from  air  in  a  bottle, 
which  has  suspended  in  it  a  spiral  of  copper  extending  from  top  to  bot- 
tom of  the  bottle.    1  c.c.  of  this  solution  will  absorb  16  c.c.  carbon  mon- 
oxide, but  it  is  best  to  renew  the  solution  after  it  has  absorbed  its  own 
volume  of  carbon  monoxide,  since  the  compound  formed  readily  disso- 
ciates in  concentrated  solution,  giving  off  gaseous  carbon  monoxide. 

These  solutions  may  be  protected  from  the  air  by  covering  the  sur- 
face in  the  outside  arm  of  the  pipette  with  a  layer  of  kerosene.  Great 
car  must  be  exercised,  however,  to  keep  the  kerosene  out  of  the  absorp- 
tion bulb  of  the  pipette,  otherwise  the  kerosene  vapors  will  increase  the 
volume  of  the  gas  residue,  and  thus  spoil  the  determination. 

EXERCISE  I. 

Analysis  of  Atmospheric  Air: — Adjust  the  reagent  in  each  pipette 
by  drawing  the  solution  up  into  the  capillary  tube  to  the  mark  just  be- 
low the  rubber  connection.  Fill  the  jacketed  measuring  burette  with 
water  out  to  the  end  of  the  capillary  tube,  then  draw  in  a  little  over  100 

120 


ANALYSIS  OF  AIR  121 

c.c.  of  air  by  opening  the  outer  vent  and  lowering  the  leveling  bottle. 
Next,  slowly  raise  the  leveling  bottle  until  the  meniscus  gives  a  reading 
of  exactly  zero,  and  the  level  of  the  water  in  the  burette  is  just  equal  to 
that  in  the  leveling  bottle. 

Oxygen: — Close  the  pinch  cocks  on  all  vents  and  open  the  one  on 
the  second  pipette,  the  one  containing  potassium  pyrogallate ;  now  raise 
the  leveling  tube  slowly,  thus  forcing  the  air  into  the  pipette.  When 
the  water  has  reached  the  100  c.c.  mark  on  the  burette,  shut  the  pinch 
cock  and  allow  to  stand  for  five  minutes.  Now  open  the  cock  and  run 
the  gas  back  into  the  burette  by  lowering  the  leveling  bottle.  "Watch 
the  surface  of  the  pyrogallate  solution,  and  as  it  approaches  the  mark 
slow  up  the  flow  of  gas — by  careful  manipulation  of  the  leveling  bottle 
the  solution  can  be  brought  just  to  the  mark  and  then  shut  off,  giving 
much  more  delicate  adjustment  than  can  be  obtained  by  manipulation 
of  the  pinch  cock  alone.  It  is  very  important  that  none  of  these  solu- 
tions get  above  the  pinch  cock,  as  the  potassium  hydroxide  in  them  in- 
terferes with  the  carbon  dioxide  determinations  in  subsequent  samples. 

Repeat  the  absorption  for  3  minutes  and  read  again.  The  contrac- 
tion in  volume  is  due  to  absorption  of  oxygen.  Calculate  the  percentage 
on  the  sample  taken. 

EXERCISE  II. 

Respired  Air: — The  apparatus  should  be  in  adjustment  after  the 
preceding  experiment.  Take  a  long  breath  and  hold  in  the  lungs  for 
some  time,  then  blow  it  into  one  of  the  rubber  balloons.  Attach  this  to 
the  outer  vent  of  the  apparatus  and  draw  in  a  sample  of  110  c.c.  as  be- 
fore. Now  close  this  pinch  cock  and  open  the  one  at  right  angle,  to  the 
air;  then,  by  raising  the  leveling  bottle  slowly,  bring  the  surface  of  the 
water  to  the  zero  mark  and  close  the  cork  opening  to  the  air. 

A.  Carbon    dioxide.    Always    absorb    the    carbon    dioxide    first 
bringing  the  gas  into  the  first  or  potassium  hydroxide  pipette.    Allow  it 
to  stand  for  5  minutes  and  repeat  for  3  mintues.    The  contraction  is  due 
to  carbon  dioxide — determine  its  percentage. 

B.  Oxygen.    Determine  oxygen  as  in  the  case  of  atmospheric  air. 
The  difference  between  the  total  contraction  and  the  first  one  is  due  to 
oxygen.    Compute  the  percentage. 

C.  Nitrogen.     This  is  determined  by  difference. 

100  o/o  —  (o/o  C02  +  o/o  02)  =  o/o  N2 

EXERCISE  III. 

Flue  Gas: — All  determinations  of  the  constituents  of  flue  gas  are 
carried  out  as  described  in  Exercise  II. 

Carbon  Monoxide  is  determined  after  oxygen  by  means  of  the  third 


122          THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC 

pipette,  allowing  the  gas  to  stand  for  8  minutes.  In  calculating  nitro- 
gen this  is  of  course  taken  into  consideration. 

Analyze  one  sample  of  atmospheric  air,  two  samples  of  respired 
air  and  two  of  flue  gas. 

Record  on  the  blank  attached  to  the  Orsat  apparatus  the  volumes 
of  gases  absorbed  so  that  the  strength  of  any  solution  can  be  determined 
at  any  time. 

CHAPTER   X 

OIL  EXAMINATION 

EXERCISE  I. 

Identification  as  to  Origin: — Weigh  carefully  a  No.  2  beaker  and 
add  10  gms.  of  oil,  then  75  c.c.  of  6  per  cent  alcoholic  potash  solution. 
Evaporate  on  the  water  bath,  stirring  well,  until  all  alcohol  is  removed. 
Take  up  the  residue  with  50  to  75  c.  c.  of  water  and  transfer  to  a  sep- 
aratory  f  unnel.  Add  about  75  c.c.  of  petroleum  ether,  rinsing  the  beaker 
with  it  and  transferring  all  washings  to  the  funnel.  (Keep  the  ether 
away  from  a  lamp). 

Shake  well  and  let  stand  over  night.  Draw  off  the  lower  solution, 
stopping  the  flow  when  the  line  of  separation  reaches  the  top  of  the  stop 
cock.  Add  another  portion  of  water,  shake  up  again  until  any  soap  that 
may  cling  to  the  funnel  is  washed  off,  and  allow  to  settle.  Draw  off  as 
before,  this  time  getting  all  the  water  solution  into  the  beaker.  Heat 
this  solution  on  the  water  bath  for  15-20  minutes,  or  until  the  odor  of  the 
petroleum  ether  is  gone.  Cool  and  make  slightly  acid  with  dilute  sul- 
phuric acid.  If  there  is  any  soap  present  it  will  be  decomposed,  yield- 
ing free  fatty  acids  which  rise  like  oil  or  curd  to  the  top  of  the  solution. 
"Weigh  carefuly  about  5  grams  of  pure  white  beeswax  and  add  to  the 
beaker,  melt  the  whole  and  allow  to  cool.  When  cold,  remove  the  cake 
of  wax,  dry  between  filter  papers,  place  in  desiccator,  and  weigh  in  half 
an  hour.  The  increase  in  the  weight  of  wax  represents  the  fatty  acids 
from  vegetable  or  animal  oils  in  the  sample  taken.  The  amount  of  oil 
corresponding  to  the  fatty  acid  will  be  represented  approximately  by 
multiplying  the  weight  obtained  by  1.04.  Calculate  the  percentage  of 
vegetable  and  animal  oils  in  the  original  sample. 

Any  petroleum  oil  present  will  dissolve  in  the  upper  layer  of  ether, 
imparting  a  color  to  it. 

EXERCISE  II. 

Specific  Gravity: — The  specific  gravity  of  oils  may  be  taken  with 
a  pyknometer  or  with  a  specific  gravity  hydrometer.  The  oil  should  be 


OIL  ANALYSIS  123 

warmed  sufficiently  to  allow  free  movement  of  the  instrument.  The  tem- 
perature must  also  be  read  and  corrected  for.  See  table  2  of  the 
Appendix. 

Where  available,  the  most  accurate  method  is  that  of  the  Westphal 
balance,  where  a  correction  for  temperature  may  also  be  necessary.  Con- 
sult the  Appendix  for  a  table  of  specific  gravities  of  standard  oils.  In 
trying  to  identify  an  oil  by  its  specific  gravity,  however,  the  analysis 
under  Exercise  I  must  be  taken  into  account,  for  many  mixtures  of 
cheap  oils  are  made  to  imitate  some  of  the  more  expensive  varieties. 

EXERCISE  III. 

Viscocity: — This  property  is  often  confounded  with  specific  grav- 
ity. The  one  is  the  time  taken  for  a  given  quantity  to  flow  through  an 
orfice  as  compared  with  water,  the  other  is  the  weight  of  a  given  volume 
as  compared  with  the  same  volume  of  water.  In  the  event  that  a 
standard  viscosimeter  is  not  available,  a  pipette  graduated  to  deliver 
100  c.c.  of  water  from  the  bulb  alone  in  34  seconds  may  be  used  as  a 
standard. 

Take  a  100  c.c.  pipette,  fill  with  water  and  note  the  time  required 
for  the  water  to  empty  from  the  ~bulb  alone.  Repeat  once.  Now  fill  to 
the  top  of  the  bulb  with  oil  and  empty  in  exactly  the  same  way.  Note 
the  temperature  of  the  oil — it  should  be  60  degrees  F.  Divide  the  time 
for  the  oil  to  run  by  that  required  for  the  water — the  quotient  is  the 
viscosity  number. 

EXERCISE  IV. 

Flash  and  Fire  Test: — Place  the  oil  to  be  tested  in  a  cup,  or  iron 
crucible,  if  a  standard  tester  is  not  available.  Place  on  a  sand  bath  and 
suspend  a  thermometer  from  a  ring  so  that  the  bulb  is  completely  im- 
mersed but  does  not  touch  the  bottom  of  the  oil  cup.  Apply  heat,  but 
do  not  have  the  temperature  rise  faster  than  2°F.  per  minute.  Keep 
partially  covered  with  a  split  glass.  Test  by  wafting  a  tiny  flame  over 
the  surface  of  the  oil  once  a  minute.  The  tip  for  this  flame  may  be  made 
by  taking  a  wash  bottle  tip  and  inserting  it  in  the  end  of  the  gas  tubing. 

For  lubricating  purposes  oils  should  not  flash  under  250° F. 

In  testing  kerosene  and  ordinary  illuminating  oils,  the  heat  is  raised 
further  until  the  gas  evolved  from  the  surface  of  the  oil  not  only  flashes 
momentarily,  but  burns  continuously.  The  first  temperature  is  the 
"flash  point,"  the  second  the  "flame  point"  or  "fire  test."  The  most 
usual  flash  point  required  for  kerosene  is  110 °F.  The  flame  point  is  20 
degrees  higher. 

On  the  same  oil  an  open  tester  will  give  a  reading  about  10  per  cent 
higher  than  a  closed  tester. 


124         THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

EXERCISE  V. 

Acid  Test: — Obtain  2  oz.  (60  c.c.)  of  alcohol  from  the  storeroom. 
Add  2  or  3  drops  of  phenolphthalein  and  run  in  slowly  N/10  potassium 
hydroxide  solution  to  obtain  a  very  faint  pink  tinge.  Now  add  10  c.c. 
of  the  oil.  If  this  is  thick,  take  a  clean  beaker,  weigh  and  run  in  about 
10  c.c.  of  the  oil  and  reweigh ;  divide  by  the  specific  gravity,  getting  the 
volume.  Now  add  the  alcohol  to  this  and  heat  up  to  100 °F.  Titrate 
with  N/10  potassium  hydroxide  to  a  permanent  pink,  stirring  well  after 
each  addition. 

If  more  or  less  than  10  c.c.  'have  been  used,  calculate  how  much 
would  have  been  required  for  10  c.c.  and  call  this  the  "acid  number." 

EXERCISE  VI. 

Maumene's  Test: — Weigh  the  beaker  and  introduce  as  nearly  as 
possible  50  grams  of  the  oil.  Introduce  a  thermometer,  and  while  stir- 
ring vigorously  add  10  c.c.  c.p.  concentrated  sulphuric  acid.  Note  care- 
fully the  rise  in  temperature. 

Petroleum  oils  rise  only  slightly,  unsaturated  vegetable  and  animal 
oils  give  a  higher  rise  in  temperature. 

Consult  table  5  in  the  Appendix  on  Maumene's  test  and  a  table  of 
the  oils  commonly  used.  Report  the  rise  as  Maumene's  Test. 


APPENDIX 

TABLE  1 
INTERNATIONAL  ATOMIC  WEIGHTS 


Atomic 

Atomic 

Symbol. 

weight 

Symbol. 

weight 

Aluminum  

Al 

27.1 

Neodymlum  

Nd 

144.3 

Antimony  

....       Sb 

120.2 

Neon  

Ne 

20.2 

Argon  

A 

39.88 

Nickel  

Ni 

58.68 

Arsenic  

As 

74.96 

Niton  (Radium 

Barium  

Ba 

137.37 

emanation)  

Nt 

22.4 

Bismuth  

Bi 

208.0 

Nitrogen  

Os 

190.9 

Boron  

B 

11.0 

Osmium  

0 

16.00 

Bromine  

....       Br 

79.92 

Oxygen  

Pd 

106.7 

Cadmium  

Cd 

112.40 

Palladium  

P 

31.04 

Caesium  

....       Cs 

132.81 

Phosphorus  

Pt 

195.2 

Calcium  

Ca 

40.09 

Platinum  

K 

39.10 

Carbon  

C 

12.00 

Potassium  

Pr 

140.6 

Cerium  

Oe 

140.25 

Praseodymium  

Ra 

226.0 

Chlorine  

....       Cl 

35.46 

Radium  

Rh 

102.9 

Chromium  

Cr 

52.0 

Rhodium  

Rb 

85.45 

Cobalt  

....       Co 

58.97 

Pubidium  

Ru 

101.7 

Columbium  

Cb 

93.5 

Ruthenium  

Sa 

150.4 

Copper  * 

Cu 

63.57 

Samarium  

Sc 

44.1 

Dysprosium  

....       Dy 

162.5 

Scandium  

Se 

79.2 

Erbium  

Er 

167.7 

Selenium  

Si 

28.3 

Europium  

Eu 

152.0 

Silicon  

Ag 

107.88 

Fluorine  

F 

19.0 

Silver  

Th 

232.42 

Gadolinium  

Gd 

157.3 

Sodium  

Gallium  , 

Ga 

69.9 

Strontium  

Sr 

87.63 

Germanium  

....       Ge 

72.5 

Sulphur  

S 

32.07 

Glucinum  

Gl 

9.1 

Tantalum  

Ta 

181.5 

Gold  

Au 

197.2 

Tellurium  

Te 

127.5 

Helium  

He 

3.99 

Terbium  

Tb 

159.2 

Holmium  

Ho 

163.5 

Thallium  

Tl 

204.0 

Hydrogen  

H 

1.008 

Thorium  

Th 

232.40 

Indium  

In 

114.8 

Thulium  

Tm 

168.5 

Iodine  

I 

126.92 

Tin  

Sn 

119.0 

Indium  

....       Ir 

193.1 

Titanium  

Ti 

48.1 

Iron  

Fe 

55.84 

Tungsten  

W 

184.0 

Krypton  

Kr 

82.92 

Uranium  

U 

238.5 

Lanthanum  

La 

139.0 

Vanadium  

V 

51.0 

Lead  

Pb 

207.10 

Xenon  

Xe 

130.2 

Lithium  

Li 

6.94 

Ytterbium 

Lutecium  

....       Lu 

174.0 

(Neoytterbium)  . 

Yb 

173.0 

Magnesium  

....<      Mg 

24.32 

Yttrium  

Yt 

89.0 

Manganese  

Mn 

54.93 

Zinc  

Zn 

65.37 

Mercury  

....       Hg 

200.6 

Zirconium  

Zr 

90.6 

Molybdenum  

Mo 

96.0 

125 


126         THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

TABLE   2 

Table  for  Calculating  the  Specific  Gravity  of  Oils  at  15.5°  C. 

C.  H.  Wright,  Jour.  Soc.  Chem.  Ind.  26,  513. 
Example:  A=sp.  gr.  at  20°     Axl.00319=sp.  gr.  at  15.5°  C. 


Tem- 

Tem- 

Tem- 

Tem- 

pera- 
ture. 

Factor 

pera- 
ture 

Factor, 

pera- 
ture. 

Factor, 

pera- 
ture. 

Factor, 

0° 

C° 

C° 

C° 

10 

0.99612 

14 

0.99894 

18 

1.00177 

22 

1.00462 

11 

0.99683 

15 

0.99965 

19 

1.09248 

23 

1.00534 

12 

0.99782 

16 

1.00935 

20 

1.00319 

24 

1.00605 

13 

0.99823 

17 

1.00106 

21 

1.00391 

25 

1.00677 

TABLE  3 

REPRESENTATIVE  SAMPLES  OF  LUBRICATING  OILS 

By  Albert  F.  Seeker, 
From  Van  Nostrand's  Chemical  Annual. 


Name, 

Sp.  Gr. 

60°  F 

Flash 

T?8t 

op, 

Fire 
Test 

O  T7» 

Cold 
Test 
°F 

Saponifi- 
able 
Matter 

Ash 

Acidity 
or  alka- 
linity. 

Air  Compressor  oil 

0  .  8857 

455 

525 

25 

trace 

none 

neutral 

Air  Compressor  oil   

0.8654 

410 

460 

-2 

none, 

none, 

neutral 

Car  oil 

0  .  8824 

354 

400 

5 

none, 

none 

neutral 

Cutting  oil 

O.i>036 

345 

425 

31 

82.9$ 

none 

1  16$ 

Cylinder  oil 

0  8921 

535 

600 

60 

20$ 

trace 

neutral 

Cylinder  oil 

0  9020 

545 

600 

31 

2.4$ 

none 

neutral 

Cylinder  oil 

0  8993 

590 

600 

none, 

0  06$ 

neutral 

Cylinder  oil 

0  8992 

555 

600 



none. 

0  08$ 

neutral 

Engine  oil  .         .  . 

0  9163 

430 

480 

27 

1.5$ 

trace 

neutral 

Engine  oil  .       .    . 

0  8845 

360 

415 

5 

10$ 

none 

0  05$ 

Engine  oil 

0  8970 

400 

465 

3 

none, 

none 

neutral 

Engine  oil   .... 

0.8810 

405 

470 

14 

none, 

C  02$ 

neutral 

150°  Fire  test  oil  
150°  Fire  test  oil  

0.7864 
0.8206 

140 
266 

180 
300 

32 

none, 
none, 

none, 
none, 

neutral, 
neutral 

High  fepeed  engine  oil  

0.9152 

400 

465 

5 

17.2$ 

0.06$ 

1  09$ 

High  speed  engine  oil  

0.9149 

400 

475 

3 

15.3$ 

0.04$ 

1  06$ 

Ice  machine  oil  

0.8941 

430 

495 

-4 

none, 

0.13$ 

neutral 

Machine  oil  

0  8689 

420 

480 

0 

trace, 

none, 

neutral 

Marine  engine  oil 

0  8812 

405 

440 

17 

none 

trace 

neutral 

Marine  eng'ne  oil 

0  8765 

435 

500 

5 

none, 

0  05$ 

neutral 

Marine  engine  oil 

0.9090 

405 

464 

0 

12.0$ 

0  15$ 

0  75$ 

Marine  engine  oil 

0  9054 

400 

470 

9 

9.0$ 

0  11$ 

0  50$ 

Screw  cutting  oil 

0  9002 

380 

425 

15 

25$ 

none, 

1  0'^ 

Transformer  oil 

0  .  8646 

365 

430 

2 

none. 

none, 

neutral 

CONSTANTS  OF  LUBRICATING  OILS 


127 


TABLE  4 

Chemical  Constants  of  Oils. 

By  Albert  F.  Seeker. 
Compiled  from  Van  Nostrand's  Annual. 


Name, 

Mixed  Fatty  Acids 

Melting  Point,  °C. 

Acid  Value. 

Iodine  Value. 

Castor     

13 
25-27 
21-25 
17-23 
34-40 
33.2-37.4 
17-21 
19.2-31-0 
26-36.4 
16-19 
31-43.8 

192.1 
258-266 
204-207 
198-4 
202-298 

87.93 
8.4-9.3 
130.5  170 
119.5      . 
111-115 

Cocoanut  

Corn  (Maize) 

Cottonseed 

Lard  Oil 

Linseed 

197 
193 
101.6 
185 
188.8 

179-182 
86-90 
96-103 
99-103 
144-159 

Olive 

Peanut  (Arachis) 

Rape  (Colza)     

Tung  (Chinese  wood  oil)  

TABLE    5 

Maumene's  test,  showing  the  rise  in  temperature  of  common  oils. 
From  Stillman's  Engineering  Chemistry,  4th  Edition. 


Name  of  Observer. 


Maumene 

Schaedler. 

Arch  butt 

Allen. 

Stillman. 

Lard  oil  

°C 

40 

°C 

°C 

°C 
41 

°C 
39  5 

Tallow  oil  

41-43 

39 

Neat's  foot  oil  

45 

50 

43 

40 

Oleo  oil  

37* 

38* 

37 

Elain  oil  

38 

Sperm  oil  

51 

45  47 

48 

Whale  oil  

92 

91 

92 

Menhaden  oil  

123-128 

126 

128 

Dog-fish  oil  

80 

Cod  liver  oil 

102-103 

103 

113 

110 

Crude  cotton  seed  oil. 

69.5 

70 

67  69 

74 

Rape  oil 

58 

60 

Castor  oil 

47 

48 

46 

65 

45 

Olive  oil 

42 

43 

41-45 

41-43 

42 

Rosin  oil  

28 

18-22 

10 

Mineral  lubricating 
oil    

3-4 

3 

Earth  nut    

67 

67 

47-60 

Sea  Elephant  

65 

Corn  oil  

85 

128          THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 


INDEX 

PAGE 

Air  Analysis  121 

Alkalinity  of  Water  86 

Calculations  92 

Total  91 

Ash  in  Coal  46 

Corrected  Ash  46 

Determination  of  95 

Penalties  for  excess  64 

Available   Hydrogen   ,.49,  54,  1 19 

Boiler  Waters  5-26 

Analysis   of    85 

Calculations  for  treatment  24 

Industrial  methods  of  purification  16,  22 

Rating   of    8,  23 

Table  with  calculations  for  treatment 26 

Calculations  involving  unit  coal  47 

Coal  values  for  commercial  guarantees 52 

In  settlement  of  contracts 63,  64 

Calculations  from  air  dry  to  dry  coal 4/1,  96 

From  dry  to  as  received 44,  96 

Calorific  Values 49 

By  calculation  from  formula  49,  53 

Computations  in  connection  with  the  oxygen  bomb in 

Oxygen  Bomb  method 108-1 14 

Peroxide  method 97,  103 

Berthier's  test  53 

Calculated  by  formula 49 

Definitions 49 

Direct  determination  54,  55,  56 

Peroxide  Bomb  method  57 

Radiation  corrections  56 

Carbon  Dioxide  in  Waters  14 

Excess  14 

Free  and  half  bound  I4 

Classification  of  Waters 8,  23 

According  to  type  of  mineral  constituents '  n 

As  used  by  the  C.  B.  &  Q.  R.  R 23 

By  the  Association  of  Railway  Chemists 8 

CoalA- :-~: - 29 

Analysis ^ 

Classification  ^o 

Deterioration  55 

Production,  annual  ™_"  29 

Sampling  ..'"'^""'"'""'^2-43 

Spontaneous  combustion  66 

Storage  "ZZZZ'Z  ".".".".66,  70 

Combustion  of  Coal  6=5 

Smoke  prevention  65 

Corrosive  ingredients  of  water  "."..."..  n 

Dry  Coal  4 

Dulong's  Formula 


INDEX  129 

PAGE 

Feldspar,  Decomposition  of  7 

Fixed  Carbon  48 

Determination  of  96 

Flue  Gas  71 

Analysis  of  - HQ 

Calculation  of  volumes  and  weights 72,  73 

Loss  of  heat  74 

Ratio  of  air  entering  to  air  used 73 

Solutions  for  analysis  of  120 

Foaming  ingredients  10 

Fuel  27 

Analysis  31 

Production    29 

Ratios 30 

Resources    _ 29 

Types  27,  28 

Gypsum,  Solubility  of  7 

Hardness  87 

Negative    ~.  88 

Permanent    87 

Total 88 

Illinois  Coals  59 

Composition  of  60 

Lime,  Use  of  13 

Hydrated  15 

Impurity  allowed  for  1 5 

Solubility  of  15 

Use  of  in  water  treatment 15 

Lubricants 76,  77 

Methods  for  testing  * 78,  122.  123 

Mineral  constituents  of  water  5 

Analysis  85-92 

Characteristics  ; 6 

Source  5 

Moisture  in  Coal.  Importance  of  Control 38 

Determination  of  _ 94,  95 

Loss  in  sampling  38 

Oils  77 

Analysis    of    122 

Specific  gravity  122 

Viscosity   123 

Sampling  of  Coal  32-43 

Amount  required  33 

Ash  variations  36 

Car  lots  38 

Care,  material  33 

Commercial  samples  32 

Composite  39 

Face  samples  32 

Grinder  for  34 

Hand  samples  32 

Mechanical  sampling  40 

Moisture  control  38,43 

Sizes  34 


130          THE  CHEMICAL  EXAMINATION  OF  WATER,  FUEL,  ETC. 

PAGE 

Scaling  ingredients   ..................................................................................................................      8 

Effect  of  ..............................................................................................................................      9 

Soda  Ash  ....................................................................................................................................     15 

Use  of  in  water  treatment  ..........................................................................................  15,  16 

Specifications  for  coal  contracts  ..........................................................................................    61 

Bids  and  awards  ............................................................................................................  62,  63 

Calculations  for  settlement  ..................................  .  .....................................................  63,  64 

Double  standard  of  reference  ......................................................................................    61 

Penalties  for  Ash  ..............................................................................................................    64 

Price  and  payment  ............................................................................................................     63 

Spontaneous  Combustion  ........................................................................................................    66 

Oxidation  stages  ................................................................................................................    67 

Standard  solutions  ....................................................................................................................     79 

Calcium  chloride   ........................................................................  .  .....................................    82 

Soap  solution  .....................................................................................................................    82 

Sodium   carbonate   ............................................................................................................     80 

Sulphuric  acid  .....................  .  ..............................................................................................     81 

Storage  of  Coal  ........................................................................................................................    66 

Deterioration  .................................................................................  .-.  ...................................    66 

Iron  pyrites,  effect  of  ......................................................................................................     67 

Methods  ................................................................................................................................     70 

Moisture,  Influence  of  ....................................................................................................     68 

Oxidation  and  heat  stages  ............................................................................................     67 

Spontaneous  combustion  ................................................................................................    66 

Weathering  .......................................................................................  .  ..................................    69 

Sulphur,  Determination  of  ....................................................................................................     81 

Curve   ....................................................................................................................................  107 

In  Coal  ................................................................................................................................  103 

In  Waters  ........................................................................................................................  81,  90 

Photometer  ..........................................................................................................................  104 

Sulphur  in  Coal  .................................................  .  ......................................................................    48 

Total  Carbon  in  Coal,  Use  of  ......................................................................................  49,  73,  u 

Apparatus   for  measuring  ..............................................................................................  115 

Determination  of  ........................................................................................................  115-118 

Table  for  weight  of  carbon  ............................................................................................  118 

Treatment  of  boiler  waters  ..................................................................................................  12-26 

Industrial  appliances  ........................................................................................................     16 

Lime  as  used  for  ..............................................................................................................     13 

Tabulated  scheme  for  ......................................................................................................  13 

Ultimate  analysis  of  Coal  ......................................................................................................  115 

Unit  Coal  ....................................................................................................................................  46 

Calculation  of  commercial  values  from  ......................................................................  46 

Classification  by  means  of  ..............................................................................................  5: 

Formula  for  deriving  heat  values  ........................................................................  """.".  50 

Formula  for  calculating  ..................................................................................................  47 

Heat  values  of  ..................................................................  50 

Volatile  matter  in  Coal  .....................................................................................................         48 

Determination    of   ..............................................................................................  \"..'".""~g5,  96 

Wrater  for  industrial  use  .......................................  5_26 

" 


Classification    .....................  .  ....................................................  8-23 

Treatment  ..  Vfi-?> 

wet  coal  .................................  zzzzizzzzzzzz  44 


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